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JOURNAL
OF THE
ROYAL MICROSCOPICAL SOCIETY:
CONTAINING ITS TRANSACTIONS AND PROCEEDINGS,
AND A SUMMARY OF CURRENT RESEARCHES RELATING TO
ZO OLO GS AND Bot AN (principally Invertebrata and Cryptogamia), DILCROSCOP YY, cee. BOT: Edited by GA FRANK CRISP, LLB. B.A,
One of the Secretaries of the Society, and a Vice-President and Treasurer of the Linnean Society of London ;
WITH THE ASSISTANCE OF THE PUBLICATION COMMITTEE AND A. W. BENNETT, M.A., B.Sc., F.LS., F, JEFFREY BELL, M.A., F.ZS., Lecturer on Botany at St. Thomas's Hospital, Professor of Comparative Anatomy in King’s College, JOHN MAYALL, Joun., F.Z.S., R. G. HEBB, M.A., M.D. (Cantaé.), AND
J. ARTHUR THOMSON, M.A., Lecturer on Zoology in the School of Medicine, Edinburgh,
FELLOWS OF THE SOCIETY.
FOR THE YEAR 1889. Part]:
PUBLISHED FOR THE SOCIETY BY
WILLIAMS & NORGATE, LONDON AND EDINBURGH.
Saas The Journal is issued on the second Wednesday of February, April, June, August, October, and December.
tay gh. : r 1889. Part 4. AUGUST. { *°pieo. snows,
JOURNAL
OF THE
ROYAL MICROSCOPICAL SOCIETY;
CONTAINING ITS TRANSACTIONS AND PROCEEDINGS,
AND A SUMMARY OF CURRENT RESEARCHES RELATING TO
ZooLucGyY AND BOTAN WZ (principally Invertebrata and Cryptogamia), MICROSCOPY, Szc-
Edited by
FRANK CRISP, LL.B. B.A, One of the Secretaries of the Society and a Vice-President and Treasurer of the Linnean Society of London ; WITH THE ASSISTANCE OF THE PUBLICATION COMMITTEE AND
A. W. BENNETT, M.A., B.Sc., F.L.S., F. JEFFREY BELL, M.A., F.ZS., Lecturer on Botany at St. Thomas's Hospital, Professor of Comparative Anatomy in King’s College, JOHN MAYALL, Jun., F.ZS., R. G. HEBB, M.A., M.D. (Cantaé.), AND J. ARTHUR THOMSON, M.A., Lecturer on Zoology in the School of Medicine, Edinburgh, FELLOWS OF THE SOCIETY.
WILLIAMS & NORGATE. es LONDON. AND EDINBURGH. 4
PRINTED BY WM. CLOWES AND SONS; LIMITED,] (STAMFORD STREBT AND CHARING CROSS.
CONTENTS.
——
TRANSACTIONS OF THE SoornrTy—
Waters or tHE Unitep States. By Dr. Alfred C. Stokes. CPTatG; RE) aoe -
VITI.—Anpprtionat Norte on THE ForaMnirera oF THE Loxpon Chay EXPOSED IN THE Drainage Works, PICOADILLY, Lonpon, IN
1885. (Plate XI.) oo ee es oe oe oe oe Ch ae 483 SUMMARY OF CURRENT RESEARCHES. ZOOLOGY. A. VERTEBRATA :—Embryology, fuel and General. a. Embryology. is Minor, c S.—Uterus and Embryo... .. ery ck opr heey rae Bote) Tarani, A.—Fecundation and Bopientalion of Ova of Rats |. Freee: SOO Cunnineuam, J. 'T.—Keproduction and Development of Teleostean Fishes apis we AON B. Histology. Frommann, 0.— Vital Processes in Living: Celery. se eae Spaeth aeae oar Morrvurco, B.—New Formation of Cells .. anette Sate em ene hes Tanaz, F. Vie ie between Cell-body and Nucleus i; i. tee ees Fatzacappa, EK.—Nerve-cells in Birds .. : . ee (494 Gace, 8S. H—Form and Size of Red 1 Blood-corpueces: of “Adult and Larval Lampreys .. v5 se owe a Pp ste Hh | y. General. STUHLMANN, F.—Fresh-water Fauna of Hast Africa .. .. «2 «se 0» «s «6 494 B. INVERTEBRATA. s Cuténot, L.—Lymphatic Glands of Cephalopods and Decapodous Crustacea .. -.. 495. Mollusca. ; a. Cephalopoda. ee Eanes Structure of Siphon and Funnel of Nautilus Pompilins eae eee EATS Brock, J.—So-called Organ of Verrill in Cephalopoda .. «. «« «ce os « 496 B. Pteropoda. PELSENEER, P.—Morphology of Spinous Saes of Coin auomnaue Preropods ae eeees? A9G y. Gastropoda. Bovuran, L.—Ventral Nervous Mass of Fissurella 9... eet as Gee Oe Prez, J.—Descent of Ova in’ Helix ea oft ciop eka aeeO W ScHALFEsEFF, P.—Anatomy of Clione Vimacina Per Spee Sei3 Se yb GARNAULT, P. —Reproductive Organs of Valvata ‘piscinalis eae wee bee See 5, Lamellibranchiata. : Méniéicaux, A.—Morphology of Teredo .. 3: awh ee nig py eige se Necmayr, M.—Origin of Unionidz ee, eed ee ae Molluscoida, a. Tunicata. Dayivorr, M. v.—Developmental History of Distaplia magnilarva.. :
PAGE VilI.—Norticzs or New PeEritRicnovs INFUSORIA FROM THE FREsH
ATT
+» 498
Ca)
8, Bryozoa. ’ Denpy, A.—Anatomy of an Arenaceous Polyzoon ~.. ai aa
Prouno, H. .—Structure and Metamorphosis of Larva of Flustréila hispida Arthropoda. Parren, W.—Segmental Sense-Organs of Arthropods .. 2. 6s ae eg nee
; a, Insecta. -Henxixc, H.—Formation and Fate of Polar Globules in Eggs of Insects
Daut, F., & D. Saanr—Viston of Insects .. oe ne we ee eee te BeRTKAU, P. Bodie ib abl gl Ut, GAstpOvacMes. i Foes ek teee A Tee eee es > Wasmann, E.—Myrmecophilous Insects... 20 S00 ae ee ee i oe ee ee
SKERTCHLY, ss B. J.— Butterflies’ Enéinies .. St BS BT ARO nT
Mrncazzin1, P.—Alimentary Canal of Larval Lanelicorns: Cs aia ae ahaee
yeaa: Mie Beer ond: Powers. 2." oak) ss: eek Be ae ee RPI See
Car.et, G.—Stigmata of Hymenoptera.. .. seen on
VorLTzKOW, A. .— Development in Egg of Musca vomitoria . Miz, J.—A Spinning Dipteron
Low, F.— Bio rele of Gall-producing Species ‘of Clhermes : ee ; dee a Pian okay “es he Sars ‘gg of Melolontha vulgaris 4; Le ER TP PEG EOE Te Hassn, E ei sees of Ld: 0 deere eens ns cinta RES A ES EA Saga 8. Myriopoda. CHALANDE, J.—Spinnerets of Myriopoda .. Se OS eC ae ph cos eat paen eta Pocock, R. I.—Myriopoda of Mergui Arehipelago Pies ePaper eta ai Rae OSE . Prototracheata.
_ SHELDON, eo Anat of Ovum in Cape and New Zealand Species of Peripatus 6. Arachnida.
Moun, A. D.—Life-histories of Ciaviphape 2 domesticus and G. one os
- Méenty, P.—Encystation of Glyciphagus .. iy x Kornrke, F.— New Genus of Hydrachnids .. Hag Cee ee Montez, R.— Accidental Parasitism on Man of Tyroglyphus farinzs.. oar pate ne ain Trovrssant—Marine Acarina of the Ooasts of France... is
Sonaus, R. v.—Marine Hydrachnida .. Fe ESE Nar ab eet Weenie We ApteRz, G.—Morphology and Larve of Pantopoda- SF SIP Y TS jae R NY Aiba Yee e
e. Crustacea. —
Rossnskaya, M.—Development of Amphipoda oi ely seeps RET eS Norman, A. M.—British Amphipoda .. 2. 42 ee ee Cuon, C. Rp te Family of Scinidz
‘Brapy, G.5., . MN oRmAN—Ostracoda of North Atlantic and d North-western Europe = Grarp, A., & J: Bonwier—Parasitic Crustacda.. f2 ay Morphology and Systematic Position of the Dajte “a Koruuer, R. —"Fequmentary Coverings of Anatifer and Pollicipes .. «+ Vermes. a, Annelida. Rove, L.— Influence. of Nervous System of Annelids on Symmetry a the Bais y Soutien, A.—Epidermis of Serpulidz .. as
BEDDARD, F.. E.— Marine Oligochzxta of Plymouth
Fiercuer, J. J.—Australian Earthworms .. BepparD, F. B.— Green Cells in Intequment of Aeolosoma tenebrarum .. Wurman, ©. O.—Anatomy of Hirudinea. .. pae reaecr es greed E. A.—Reproductive Organ of Phascolosoma Gouldii =. i
B. Nemathelminthes.
Gotpr, E. A.—Coffee-Nematodeof Brazil... eee ce te we te we - Srosstcs, M.—Physaloptera .. Peet See RN tees yb - Kyiprrer, P.—Female Genital Duets of Acinnthocepkata SS See Rese ee ERE Se
PAGE 499 501
501
502 502 503 503 504 504 904 505 505 506 506 506 506
507 507
507
908 509 509 509 509 509 509
910 oll 512
912 512 514 913
514 515 515 515 515 516 518
518 518 519
(4)
y. Platyhelminthes. PAGE. Wenpt, A.—Gundauloz ... dt a ae i ae a eee Bireer, O.— Nervous System of Nemertines.. Pp Pa aa ER eS Linstow, von—Helminthological Notes... .. Perit wer a is Pe Stosstcu, M.—The Species of Distomum in Amphibians Foo gle <2 jo wen Sear ae eae Listow, von-—Anatomy of Phylline Hendorfitt .. s,s» se ee we ee we DAD Monticetui, F. §.—Nervous System of Aniphen lee wok fGct agnor hen pena iy Cercaria setifera .. «. go Slee agin be eaaag pies ene Crery, C.—Structure of Rolenophorus We top Dies hu we 5 wage akan tee a 523 5. Incertee Sedis, Ming, W.—Rotifers Parasitic in Sphagnum © 1. se +e en tee te OB Keuuicorr, D. S.—American ROL fEP Os oe ioe Kas oi belies aah tape eee oe eae aes Bourne, G. C.—Tornaria in British Seas... 12 ae ve ee we we we we ORD Echinodermata, oe Lupwie’s Echinodermata . wii} Ret em. ieee en eee antes Hamann, O.—Anatomy of Ophiuroids and Crinoids MY eC ster ne ate ns rd) JickELI, C. F.—Nervous System of Ophiurids .. ee 00 se ee we we we OT Hamann, O.—Morphology of Crinotds’.. ss % os oe a» oe ne we we ae 028 Beui, F, Jurrrex—Large Starfish ee prt sn Ives, J. E.— Variation in Ophiura panamensi and O. teres... er? dee ee DAO, Coelenterata. MarsHaui, A. Mitnes, & G. H.. Rowrius Seen ues i Mergui Archiplag oo 529 M‘Morricx, J. P.—Lebrunia neglecta ..~ .. na ee ae oe 929 Siuirer, CG. P.—Remarkable Actinian® .. sui st sn) oe Uwe) aa) 20 ne ee ew Kocu, G. v.— Caryophyllia rugosa .. SA Se 9 aes Sete OU: VANHOFFEN, E.—Semxostomatous and Rhizostomatous Medusz.. Fa ae eee Seo Cuun, C.—Siphonophora of Canary Islands... ss ee ne ne te we ws, 30 Fewses, J. WauteR—New Athorybia .. se 2k ae Jen ee ee ae ae ae ScHEWIAKOFF, W.—LHyes of Acalephe .. -+ ee 46 an ne pe ne ee 532 Porifera. ; Tnmy, J.—Clona= on oes sa oe at kee me ie aime ee Protozoa. z ‘ . Fapsre-DomerGue—Functional Differentiations in Unicellular. Betude Shas thes 534 GruBer, A.—Maupas’ Researches on Ciliata =... su ce we we ne we we ODE FABRE-DOMERGUE—Two New Infusorians .. .. ss s+ ss se «8 er se 980 ANDERSON, “a H.—Anoplophrya aeolosomatis .. ance hem gan eee Lee eta F.— Formation of Spores of Gregarie of Harthworm «036 © Luz, A.—Cystodiscus wmmersus—a paghe ee ec found in the gall-bladder of : Brazilan Batrachia pele aes Sree Pam ea re ee Sie wo Aye BOTANY. A. GENERAL, including the Anatomy and Physiology” of the Phanerogamia. a. Anatomy. (1) Cell-structure and Protoplasm. : SrrasBuRGER, E.—Growth of the Cell-wall .. 2. se as em eae | oe se D8 Manein, L.—Structure of the Cell-wall . ae MMP ENE arrestee ST te) Vrins, H, pe—Permeability of Protoplasm for Urea .. 538. Kroricky & Bie~kowsky—Diosmose through the Cellulose-pellicle of Phragmites contr ieds ‘ Fe ate a Breas 539 PFEFFER, W — Reduction of Ripe in the living- cell EO ae Da ae Poe
539
(oa)
(2) Other Cell-contents (including Secretions).
Scuuncg, E.—Chemistry of Chlorophyll... eecvobe Wen” ie Moutscu, H.—Formation of Chlorophyll by Conifers i bi tlia Wark. a6. as uy hae Boum, J.—Formation of Starch in the Leaves of Sedum spectabile” ..
MOELLER, H.—Mode of occurrence of Tannin in Plants
(3) Structure of Tissues.
Ross, H. an ale Tissue and Periderm in leafless plants...» + +» + Paprennetm, K.—Closing of the Bordered Pits in ania Rite DAwy. os ways ewe TAGRIEE, M, O.—Structure of Lecythidacer.. .. A ites Pros: eer Re.
(4) Structure of Organs. aie bea E.—Anatomy and Chemistry of Petals sakceni ee
RAtuay, E.—EHxtrafloral Nectaries.. .. Sue Se RU aa ae a aor ee op Correns, E. C.—Extrafloral Nectaries of Pigosuidie sic he Merenan, T.—Elastic Stamens of Composite... .. RE UAE SOP Pe ae oe 35 » Glands on the Stamens oF Caraee yllacer Preis meine wae A went ee Heimert, A.— Fruit of Nyctaginer .. Era Paper ag tie LorseL, O.—Anatomy of Leaves .. .. pec gie Sek Spee aga wes chests ee Krasse, G.—Fixed daylight position of Leaves as oneal
Biscun, M —Structure and Function of the Bladders ‘of Uiricutaria ScuwENDENER, S.—Stomates of Graminex and Cyperacexr STRUBING, O.—Stomates of Conifere .. oe ae ae we
TURNBULL, R.—Water-pores in Cotyledons .. 2. se ae tenet ee Frot, L.— cae a of Trees .. .. Piers ieee lator tet E.— Bacillax Tumours of the Olive and of Pinus halepensis ae Page oa De.rino, F.—Tubercles on the Roots of Galega officinalis .. .. ss. ++ 08 we Histncer, E.—Tubercles of Ruppia and Zannichellia .. Page ear aes OR ee Borzi, A.—Lateral Roots of Monocotyledons.. .. 2. ee se tte wwe
B. Physiology. (1) Reproduction and Germination. Vaiss, H. pse—Intracellular Pangenesis =... 4. ae
ee ROR at Nn eer acer rae pte ¥ ‘Lupwie, F.—Fertilization by Braghees sc Wek Coe oe Ce toe
(2) Nutrition and Growth (including Movements of Fluids).
WortTMAnn, J.—Physiclogy of Growth .. 6. ss nate ene weet Wiesner, J.—Descending Current of Water... wah ties’ 26 eNpu we Dovrior, H.—Influence of Light on the Development of Bark . ae Guupr, L, A.—Periodical Activity of the Cambium in the Roots of Trees Apa e Mayen, L.— Penetration and Escape of Gases in Plants ., .. 0s ve oe we FRANK, B.—Assimilation of Free Nitrogen by the Lower Organisms... .s «»
(4) Chemical Changes (including Respiration and Fermentation).
Loum, C. Pc sebog of the Fig.. PSOE Aer OFS Me a ep
leis .—Process of Oxidation in Living Cells Eat RE ue ak De a oe
Zor‘, W.—Oxalic Fermentation 1. se ee ne eet tee y- General.
Gorset, K.—Young State of Plants... .. .. Soraver, P.— Tan-disease” of Cherries Harric, R.— Diseases of Trees .. ..
B. CRYPTOGAMIA.
Cryptogamia Vascularia.
Cuvuncu, A. H.— Aluminium in Vascular Cryptogams ihe eat a ie, Ree Farmer, J. B.—Germination of the Megaspore of Isoetes., .. «1 6s ae
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541 542 942
542 543 543 544 544 544 544 545 545 545 946 546 546 546 546 — 547 547
547 548 548
548 548 549 549 549 550
550 550 550
550 dol dol
551 ool
es
GuienaRD, L.—Antherozoids of Ferns ...
SABLON, LECLERC Du—Stem of Ferns
Lows, E. J.—Varieties in Ferns .. as RasBeENHOoRST's Cryptogamic Flora of Germany (Fasoutar Cryptogams) oF Srenzet, G.—Tubicaulis.. ..
Muscines, Amann, J.—Leptotrichic Acid sighs toe PANN wake eet Gennes, A.—Mosses from New Guineas, -.. Gciaanea GuienarD, L.—Antherozoids of Hepatice and Mosses hepa HABERTANDT, H.—Geotropism of the Rhizoids of Marchantia and Lunularta. fe
Algee.
Picoone, A. — Connection of the geographical distribution of mee iit. the @ chemical
nature of the substratum
ASKENASY, -E., ann OTHERS—Algz of the * Gazelle’ ? Expedition Bae cee Pacman WILLE, N.—Development of Tissuesin Floride® .. 00° vee ae ae Ae at
Rosenvines, L. K.—Frond of Polystphonia ber hee Wie, N., anp J. G. AGarpH—Apical Cell of. Lomentaria and Champia Siete BAneen, C. A—Bulb of Laminaria bulbosa = een ee Varies, H. DE—Contraction of the Coren es of Spirogyra eee palev an Wiipreman, E. De—Variation in Desmids .. Bee! MouRBAY, G., & L.A. hears eae oe Works, (epee — Urospora Fs SoS aeons
TONI,. GB. DE—Clionyphe .. eee ees
Murray, G., & L.A. Booptz—Avrainvillea
Nou, F.— —Cellulose-fi bres of Caulerpa .. gs See Bitar es
Kiem, L.—Volvox .. SGPC Oca
a Sir W., & D. P. Penuattow—Ne ematophyton ins
Fungi, Zorr, W.—Fungus-pigments _ Kirasato, §.—Musk-fungus ... GiaRp, A.—New Eniomophthoraceze Maenus, P.—Urophlyctis Kriegeana sp. n.
KircayEr, O.—LHlzomyces, a new type of Fungi «. 3 os Ae : a Sep a
Bonnier, G.—Synthesis of Physcia parietina .. nae ita omene pene
Cooke, M. C., & G. Masses—New development of Enphelis RRR eye a
Rovmecvine, C.—Disease of Chestnut-trees.. .. Piet
Mryasz, Kingo—Léfe-history of Macrosportum parasitieum ssa Choate Sweet stent Menge
CAVARA, F.— American “ Bitter-rot” Se ree ee er Cosrantin, J.—Cladosporium her Barun 258 3 oe Se ee Lupwie, R.—Microscopic twining Fungus x
Direten, P.—Heterospory of Gymnosporangium a i, ‘ - ee 5 ee a : SoravEr, P.—Mildew of the Apple... .. .. Baht) BAe hice eh cae ete RC aR ee tate
KLpBABN, H.—Uredinezx of Pinus Strobus per nig bel eg A CNS ARI ee eee ae eas PATOUILLARD, N.—Coleopuccinia .. - pal renieate CosTantin, 3 pe — Tulasnella, Prototremella, and Pechylerigna a ae A Marre.ui, U.—Phosphorescence of Agari icus olearius . aie Arkinson, G. F.—Phosphorescent Mushroom
Beck, G. Rirrer v.—Poroptyche, a new genus or Poly more Cz eee Ae AMANN—Mycose on the Sporange of Mosses .. . nie Fath eae er acai etd Protophyta
a, Schizophycez. Gort, C.—Peroniella, a New Genus of Schizophycezx
Connincuam, D. D.—Stomatochytrium, a new genus of Endophiytie Profoooccaces,
HANsGire, A. —Tetraedron ? bie dey TERRY, W. A.—Movements of Diatoms ‘and Oscillaria oat) Seki aegis Wow oe Stn, T. F.—Valve of Pleurosigma —.. TUNEa ON OES RL, tore h Cain, C. H., & BE. A. Scavutze— Fossil Marine Diatoms 3 oo fe
: ‘PAGE :
Cts
Maccutati, L.—Synedra pulchella Ktz., var. abnormia . abekgee A:— Classification: of Cyanophycea » Pranti, K.—Parasitism of Nostoc meee ks
B. Schizomycetes.
Wrinocrapsky, T., & A. Hansarra—Morphology and Physiology ee the Peta Bacteria ..
Housoewntxorr—Baeteria which produce Sulplureted Hydrogen seo Jackson, C. Q.—Bacillus of Leprosy ‘ Aes ces Cuavyrnau, A.—Vaccinal Properties of Microbes. Huerre’s Bacteriology .. Marvcct, A. — Tuberculous Injection of the Fowl: “embryo “3 KARLINSKI, J.—Bacillus murisepticus pleomo? plas a new pathogenio Schisomyoete Firtscu, G.— Variations of Vibrio Proteus... i ae Nuvuavuss, R.—Flagella of the Cholera Bacilli Bees:
ESN P., & G. SANNA-SALARIS—Glischrobacterium oe Heinz, A _—Mucous Disease of Hyacinths .. 6. 4a ey Tanoysky, O. G.—Bacteriology of Snow... we we
MICROSCOPY. a Instruments, Accessories, &c.
(6) Miscellaneous. Govt, G.—* The Compound Microscope invented by Galileo”
PAGE 566 567 567
567 567 568 568 569 569 570 570 571 571 572 572
574
APERTURE TABLE.
0-66 | 82° 36’ 59° 30’ 51° 28' 63,631 68,972 83,819 © 0-64 | 79° 36’ 57° 31’ 49° 48’ 61,702 66, 882 81,279 0°62 | 76° 38’ 50° 34’ ASOD. 59,774 64,792 78,739.
Corresponding Angle (2 u) for Limit of Resolving Power, in Lines to an Inch, , ‘| Pene- Numerical} aa eee oN ee Re Re trating - Aperture. || Air Tater TOROS CREO White Light. | (Blue) Light. | Photography. “| Power. SEES i Reena a mMersrow Fr = 05269 pw, | (A= 074861 gu, | (A = 0"4000 m, 2 aoe, EN amalie= By) 1p ce ete LD a Atala Line E.) Line F.) near Line ih.) | - 3 a 1°52 we a 180° 0’ 146,543 158,845 193,037 | 2°31 *658 1-51 | es ae 166° 51’ 145,579 157,800 191 , 767 ‘ f° +662 1-50. |] £3 a 161° 23’ 144,615 156,755 190,497 Zi "667 1:49 | * oie 157° 12' 143,651 155,710 189,227: -2°220 § “671 1°48 H cs sr 153%:39! 142,687 154, 665 187 ,957- ah “676 1-47 =| 5 ot 150° 32’ 141,723 153, 620 186,687 % “680 1-46 es we 147° 42’ 140,759 152,575 185,417 ; “f- *685 1°45 i] de es 145° 6’ 139,795 151,530 184,147 “10% +690 1°44 | “ie a 142° 39! 138, 830 150,485 182,877 -074 - +694 42452 oe “3 140° 22’ | 137,866 | 149,440 | 181,607 -045. | +699 1:42 es < 138° 12° 136,902 148,395 180,337 | 2: +704 1°41 ea a 136° 8 135,938 147,350 179,067 ~*709 1:40 a se 134° 10’ 134,974 146,305 177,797 — é | 714 1:39 ey, 53 132° 16’ 184,010 145.260 176,527 F fF +719 1:38 aN “ 136° 26’ 133,046 144,215 175,257. 1:90: *725 1:37 ee a 128° 40’ 132,082 143,170 |; 173,987 : _ 729 1:36 as AA 126° 58’ 131,118 142,125 172,717 < “730 1°35 ss 5 125° 18’ 130,154 141,080 171,447 4 1- “TAL 1:34 ne = 123° 40’ 129,189 140,035 170,177 | -1: *746 1°33 32 180° 0’ | 122° 6 128, 225 138,989 168,907. 3 ea iy 1:32 oe 165° 56’ | 120° 33’ 127,261 137, 944 167,637 2 “758 1°30 = | 155° 38’ |.117° 35’ 125,333 135, 854 165,097 | 1: +769 1:28 st 148° 42’ | 114° 44’ 123,405 133,764. |- 162,557 |. 1: ; 1781 1-26 are 142° 39’ | 111° 59’ 121,477 131,674: | 160,017 "20 7794 1:24 ae 137° 36’ | 109° 20° 119,548 129,584 157,477 | 1: *806 1:22 a5 133°. 4’ | 106° 45’ 117,620 127,494 |: 154,937 | 1+ *820 1-20 oe 128° 55’ -| 104° 15’ | 115,692 125,404 152,397 -1:440- *833- 1°18 eG 5 IAS yedereers anaes joe LO Weees) ty 113,764 123,314 149, 857 Le *847 1:16 Spe | AOD: 99° 29! 111,835 121,224 147,317 © o % * 862 1-14 AS 118° .0’ See ba bd 109,907 119,134 144,777 I °877 1-12 Bie 114° 44’ 94° 55! 107,979 117,044. 142,237 * +893 1°10 es 5 111° 36’ 92° 43! 106,051 114,954 139,698 ‘210° | +909 1:08 Se 108° 36’ 90° 34’ 104,123 112,864 | 137,158: “166- *926 1:06 ap 105° 42’ 88° 27" 102,195 110,774 134,618 -124 | -943- 1:04 ie 102° 53’ 86° 21’ 100,266 108, 684 132,078 5 | 962 1:02 ag 100° 10’ 84°. 18° 98,338 106,593 129,538 “0: “980 1:00 180° 0’ oy ieee) 82° 12 96,410 1045503 126,998 - | 1-000 0-98 Ey eee y 94° 56’ 80° 17’ 94,482 102,413 124,458 1:020 0:96 147° 29’ 92° 24’ 78° 20! 92,554 100,323 121,918 J 1:042 - 0:94 | 140° 6’ 89° 56’ 76° 24’ 90,625 98,233 |. 119,378 1-064 0-92 | BB 3225 1" 87° 32’ 74° 30’ | 88,697 96,143 116,838 - 1087 0-90 || 128° 19’ 85° 10’ 72° 36’ 86,769 94,053 114,298. T-111 0-88 | 123° 17’ 82° 51’ 70° 44’ 84,841 91,963 111,758 1°136_ 0-86 _|| 118° 38’ 80° 34’ 68° 54’ 82,913 89,873 109,218 1/163 0°84 || 114° 17’ 78° 20' 67° 6 80, 984 87,783 106, 678 1-190 0-82 | 110° 10’ 76° 8’ 65° 18’ 79,056 $5,693 104, 138 1-220 0-80 _|| 106° 16’ 73° 58’ 63° 31’ 77,128 83,603 101,598 - | 1-250 0°78 || 102° 31’ 71° 49’ 61° 45’ 75,200 81,513 99,058 1:282 0-76 || 98° 56’ 69° 42’ 60° 0’ 73,272 79,423 96,518 17316 0°74 95°o28" 67° 37’ 58° 16’ 71,343 77,333 93,979 1°351 0-72 - || 92° 6’ 65° 32’ 56° 32’ 69,415 75,242 _ 91,489 1°389 0-70 =|) -88° 51’ 63° 31’ 54° 50’ 67,487 73,152 88,899 -1°429 0°68 ~| 85° 41’ 61° 30’ 93°. 9! 65,559 71,062 86,359 7 1471 1: i 1: 1y- 1: 1: 1: 1: 1,2
0-60 || 73° 44’ | 53° 38’ | 46° 30’ 57,846 62,702 76,199
0-58 || 70° 54’ | 51° 42' | 44° 51" | 55,918 60,612 73,659 724 0°56 || 68° 6 | 49° 48’ | 43° 14° | 53,990 58,522 71,119 786 0°54 || 65° 22' | 47° 54’ | 41° 37° 52,061 56,432 68,579 852 0-52 | 62° 40° | 46°° 2’ | 40° 0’ | 50,133 54, 342 66,039 923 0°50 | 60° 0 | 44° 10° | 38° 24 | 48°205 52,252 63,499 “000 0:45 || 53° 30’ | 39° 33’ | 34° 27 | 43,385 47,026 | 57,149 222 0-40 | 47° 9 | 35° 0’ | 30° 31’ | 38.564 41,801 50,799 2-500 0-35 | 40° 58’ | 30° 30’ | 26° 38’ | 33,744 36,576 44,449 | 2-857 0°30 | 34°56’ | 26° 4° | 99° 46’ 28,923 31,351 38,099 |: 3°338 0:25 28° 58’ | 21° 40' | 18° 56’ | 24.103 26,126 31,749 . 4-000 0-20 §| 23° 4° | 17°,18' |. 15° 7 19, 282 20,901 25,400 : 5-000 0-15 17° 14’ | 12° 58’ | 11° 19’ 14, 462 15,676 19,050 6-667 0-10 11° 29' | 8° 38" 7° 34’ 9,641 10,450 12,700 10-000 O05. | 5°44 | 4° 18’
Be 46’ 4,821 5,226.3) 7 8,350 -003 [20-000
COMPARISON OF THE FAHRENHEIT AND CENTIGRADE THERMOMETERS.
. Fahr. Centigr, Fahr. Centigr. Fahr. Centigr Fahr. Fahr Centigr Pak NES ee ae) °o ° ° f°] ° ° ° ° °o ° 212 100 58 70 104 40 50 10) - 4 - 20 0-2 99 156"2 102°2 89 48-2 9 - 58 | =2] 210 98°89 156 68:89 102 38°89 8:39} - 6 - 21°11 2084 154°4 100°4 38 46°4 8 - 76 | -22 208 97°78 154 67°78 100 87°78 46 7784- 8 — 22°22 206°6 152°6 98°6 37 44°6 7 - 94 | -938 206 96°67 152 66°67 98 36°67 44 6°67 | -10 — 23°33 204°8 150°8 96°8 36 42°8 8 = 11°2 | -24 95°56 150 65°56 96 35°56 42 5-56] —12 — 24°44 95 149 5) 95 35 41 5 -13 - 25 202 94°44 148 64°44 94 34°44 40 4°44] —~]4 — 25°56 201°2 94 147°2 64 93*2 84 39°2 4 - 14°8 | -236 93°33 146 63°33 92 33°33 88 3°33 | -16 — 26°67 199+4 93 145°4 6 91°4 83 37°4 3 - 16°6 | -27 198 92°22 62°22 90 32-22 36 2°22] -18 — 27°78 197°6 143°6 89°6 82 35°6 2 — 18°4 | -98 196 91-11 142 6111 88 31°11 384 l-ll | - 20 — 28-89 1958 141-8 87°8 81 33°8 1 — 20'2 | -29 194 90 140 60 86 30 32 0 - 22 - 30 192°2 89 138°2 84-2 29 30°2 pte | — 23°8 | =-81 192 88-89 138 58°89 84 28°89 30 = lllj] —24 =- 3lell 190°4 13864 82-4 28 28°4 - 2 —- 25-6 | -382 190 87°78 186 57°78 82 27°78 28 - 2:22] -96 — 32°22 188°6 134°6 80°6 27 26°6 - 3 — 27-4 | -338 86°67 134 56°67 80 26°67 26 - 3°33] —28 = 33°33 186°8 132°8 78°8 26 24-8 ae = 29°92 | —- 34 186 85°56 132 55°56 78 25°56 24 = 4:44] -30 = 34:44 185 85 131 55 77 25 23 =- 5 - 31 - 35 184 84°44 130 54°44 76 24°44 22 —- 5°564 - 32 — 35°56 183*2 84 129-2 54 75°2 24 21°2 - 6 — 32°8 | -86 182 83°33 128 53°33 74 23°33 20 — 6°67] -— 34 — 36°67 181-4 127-4 5 73°4 23 19°4 - 7 — 34°6 | - 87 180 82+22 126 52°29 2, 22-22 18 - 7°78) -36 = 37°78 179°6 125°6 5 71°6 22. 17°6 - 8 - 36°4 | - 38 178 81-11 124 51'1l 70 21°11 16 - 8:89} -—88 — 38°89 177°8 123°8 5 69°8 21 158 - 9 - 38:2 | - 89 176 80 122 50 68 20 14 -10 - 40 - 40 174:2 79 120-2 4 66°2 19 12°2 =l1 — 41°80) —41 174 78°89 | 120 48°89 66 18°89 12 - ll-ll}] -4 = 41:11 172°4 8 118°4 64°4 10°4 -12 - 43°60) - 42 172 77°78 118 47°78 64 17°78 10 — 12-22] —-44 = 42-92 170°6 116°6 4 62°6 17 8: -13 — 45°40/ -43 170 76°67 116 46°67 62 16°67 8 - 13:33] - 46 — 43:33 168°8 114°8 4 60°8 16 6°8 -14 — 47:20| -~44 168 75°56 114 45°56 60 15°56 6 ~ 14:44] - 48 — 44°44 167 75 113 45 59 15 5 - 15 - 49 - 45 166 74°44 | 112 44°44 58 14°44 4 - 15°56] -—50 = 45°56 165°2 74 111-2 57°2 3°2 -16 — 50°80| —- 46 73°33 | 110 43°33 56 13°33 2 — 16°67] — 52 = 46°67 163°4 73 109°4 554 13 1*4 - 17 — 52°60) - 47 162 72°22 108 42°22 54 12°22 1 — 17:22] -54 = 47°78 161°6 72 107°6 53°6 12 re) = 17°78} — 54:40} - 48 160 71°11 106 41°11 52 ll-1l J — 0°4 -18 - 56 = 48°89 159°8 71 105°8 51°8 1 -1 - 18:33] - 56°20) -49 9 -2 - 18-89 | - 58 - 50 = 2:2 -19 ee a
FAHRENHEIT
40 30 20 10 0 10 20 30 40 50 60 70 80 GATTI 212 LA CUT LT
TIT 40 2 20 10 0 10 20 30 40 50 60 70 80 %0 100 eee ee See
( 10
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GREATLY REDUCED PRICES — OBJECT-GLASSES MANUFACTURED BY
R. & J. BECK,
68, CORNHILL, LONDON, E.C.
PRICES OF BEST ACHROMATIC OBJECT-GLASSES.
pues Linear magnifying-power, with Seach
a Focal lost res Price. body-tube and eyespieees ture about No. 0) No 2 No. 8./No. 4 No. 8, A Dig Se Os : : 100 | Zinches .. .. 9 : 10 8 10 16 |. 30 |. -40 me 3 inch cae Mave 110° xt to aides Oe ee } ese eee ie oat 108 | 2 inches To 110:0)\° ‘ 104 | 2 inches S 210 0 \ 22 36 67 90 Ti2 106 es incl “ 23 2 2 ° 39 48 90 | 120 150 2 ine 3 2
107 | 2 inch 210 0 \ 72) 112 | 210 | 2801 350 108 | inch. 45 210. O| 100 160] 300} 400 500 109 | +,inch .. 65 4 0O O} 125 | 200) 375 | 500 625 ALO. inch ber. s te igs 5-0 0} 150] 240 | 450 |° 600}, 750 111 Z Inch oes sees Se 15 310 0 200 |, 320 | 600} 800 1000 142) 2 inch un ae a, | $120 410 0}. 250.| 400°} 750 | f000 | 1250 PLB 2 tnd fe OK gO 5 O O}| 4001} 640 | 1200) 1600) 2000 ~ 114 |, imm. ev LT BO 5 5 O71 500} 800.) 1500 | 2000 | 2500 115 |: imm. .. .. | 180 | 8 O O| 750 1200] 2250} 3000°| 3750 ~ 116 |= imm. .. .. | 180 | 10 O O'| 1000 | 1600 | 3000 | 4000} 5000" 117.| p,inch.. .. .. | 160 | 20 O OQ | 2000 | 3200 | 6090 | 8000 | ro,0¢0
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Angle No. Focal length. aper- Price. ture, about ps ES, 7 des 150 | 8 inches 6 1.0 0 | 151 | 2 inches yA oe 8 +-1°0 0 Dip ey Sone c farce aca ie 18 1°50 PS 4) inch a ae) ee ee 1.5 O V5 42 inchs oe ts 80 15 0 155 1-2 inch oe ie ort | LO 2.5 0 156 a IDCH es eee | TO 310 0 157 | 3; imm. EAR peared Ree 09) 6 0 0
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R. & J. BECK,
Here ti ee ond OG LAN b' Oy a iy a tiga R
Dey! Bess,
JOURN.R.MICR.SOC 1889 P1.X.
Newman lith.
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JAN 20 1903
JOU-BNA Ly epee GARDEN OF THE
ROYAL MICROSCOPICAL SOCIETY.
AUGUST 1889.
TRANSACTIONS OF THE SOCIETY.
VII.— Notices of New Perttrichous Infusoria from the Fresh Waters of the United States.
By Dr. Aurrep OC. Sroxzs. (Read 8th May, 1889.) PLATE X. Epistylis vittata sp. nov., fig. 1.
Bodies elongate-ovate, less than three times as long as broad, widest centrally, tapering posteriorly, slightly constricted beneath the peristome ; cuticular surface finely striated transversely, the posterior one-fifth also longitudinally striate; peristome border broad, not everted, not revolute, but when expanded slipping backward and in- vaginating the anterior border of the body as by a broad, somewhat concave band, both margins of which are usually crenulate ; ciliary disc convex, prominent; ciliary circles four; nucleus long, band-like, much curved, often irregularly constricted; pedicle profusely and dichotomously branched, becoming brown with age ; ultimate divisions of the foot-stalk about as long as the extended body; zooids many, often one hundred or more in number ; contracted bodies obovate, posteriorly annulate in several transverse folds, anteriorly plicate, the contracted ciliary disc frequently conical or snout-like ; endoplasm granular, often brownish. Length of bodies 1/120 in.; fully de- veloped colony 1/5 in. in height, conspicuously visible to the naked eye. Hab. Fresh water, attached to the shell of Physa.
Epistylis elongata, sp. nov., fig. 2.
Bodies elongate, less than four times as long as broad, widest centrally, tapering thence posteriorly, the sides of the anterior region nearly parallel or slightly tapering; cuticular surface very finely
EXPLANATION OF PLATE X.
Fig. 1.—Zpistylis vittata, ! Fig. 6.— Vorticella conosoma. ue — | sy elongata. | >» I a Conochili.
» o— >» Gutumnalis. » 8.—Opisthostyla globularis, + 7 ramosa. » I 3 similis.
” a » o—Pyxidium nutans.
1889. 2
478 Transactions of the Society.
striate transversely ; peristome border thickened, not revolute, when expanded slipping back for a short distance about the anterior extremity of the body, as in Epistylis vittata, but not concave; ciliary disc prominent, convex and cushion-like ; ciliary circles apparently three ; nucleus band-like, much and variously curved in the anterior body- half, often transversely placed ; contractile vesicle spherical, situated far forward, apparently in the ciliary disc ; endoplasm finely granular ; pedicle dichotomously and profusely branched, longitudinally striate, the primary portion about equal in length to an extended body, the ultimate divisions from one-fourth to one-fifth that length; zooids numerous ; contracted bodies ovate, often pendent, posteriorly annulate in three or four folds. Length of extended body 1/240 in.; height of entire pedicle 1/56 in. Hab. Pond water; attached to rootlets of Lemna.
Epistylis autumnalis, sp. noy., fig. 3.
Bodies conical-campanulate, three times as long as broad, the cuticular surface very finely striate transversely ; peristome exceeding the body in width, everted and revolute; ciliary disc obliquely elevated; ciliary circles two, the outer wreath projecting almost horizontally ; nucleus band-like, curved, transversely placed in the anterior body-half; contractile vesicle single, spherical, anteriorly located apparently within the ciliary disc; contracted body obovate or subspherical, posteriorly annulate, and invaginating the extremity of the foot-stalk; pedicle dichotomously branched, more or less flexuose, longitudinally striate, the ultimate divisions about one- third as long as the extended zooids, the main stem about one-half the length of the entire pedicle, the whole becoming brown with age. length of extended body 1/300 in.; height of entire pedicle 1/65 in. Hab. Pond water; attached to the rootlets of Lemna, in the autumn.
Epistylis ramosa, sp. nov., fig. 4.
Bodies elongate-ovate or elongate-subvasiform, less than four times as long as broad, widest subcentrally, tapermg posteriorly to the pedicle and anteriorly to a short, subeylindrical, neck-like prolongation, the frontal border truncate, crenulate; cuticular surface very finely striate transversely ; peristome narrower than the body centre, neither revolute nor much everted; ciliary disc obliquely elevated ; ciliary circles apparently two; pharyngeal passage very capacious, extending beyond the centre of the body, its walls conspicuously ciliated ; pedicle finely striate longitudinally, profusely and dichotomously branching, the divisions in mature colonies forking from eighteen to twenty times, the ultimate branches about one-half the length of an extended body, the entire foot-stalk becoming brown with age; contracted zooids - elongate-obovate, nodding, invaginating the summit of the pedicle and posteriorly annulate, bearing anteriorly a short, longitudinally plicate, snout-like projection, the frontal border crenulate; nucleus band-like,
New Peritrichous Infusoria, de. By Dr. A. C. Stokes. 479
broad, curved, transversely placed in the anterior body-half. Length of body 1/225 in.; colony often measuring 1/15 in. in height. Hab. Pond water, in the autumn.
Pyaidium nutans, sp. nov., fig. 5.
Body elongate-subfusiform, about twice as long as broad, some- what gibbous, widest centrally, tapering posteriorly to the pedicle, slightly constricted beneath the truncate, finely crenulate peristome border; cuticular surface smooth; ciliary disc conspicuously and obliquely exserted; ciliary circles two, the second wreath extending almost horizontally ; vestibulum capacious, extending to near the body centre, strongly ciliate, a long, curved, and conspicuous vesti- bular bristle present; pedicle short, about one-fifth as long as the body, variously and irregularly undulate; contracted body obovate, suddenly nodding, the posterior region inconspicuously invaginating the anterior termination of the pedicle, and variously and irregularly annulate, with an anterior snout-like projection. Length of body 1/450 in. Hab. Pond water; attached to the rootlets of floating aquatic plants. Solitary.
Vorticella conosoma, sp. nov., fig. 6.
Body conical, soft and flexible, transversely striate, about four times as long as broad, widest at the frontal margin, tapering thence to near the attachment to the pedicle where it is continued as a minute, subeylindrical prolongation, frequently showing at the begin- ning of the posterior third a slight transverse constriction ; peristome border everted, not revolute ; cilia short ; nucleus transversely placed in the anterior body-half, short, broadly band-like, and much curved, in certain positions of the body apparently ovate; pedicle filiform, from two to three times as long as the body, the muscular thread distinct. Length of body 1/375 in. Hab. Attached to the gelati- nous tubules of Conochilus volvow.
This interesting form was first observed attached to the same colonies of Conochilus which bore the Vorticella Conochili, to be next referred to, but in much less abundance, not more than two having been noted on the same cluster of Rotifers. Although the muscular thread is distinctly developed it seems seldom to exercise its contractile
ower. 2 The body when contracted becomes elongate-obovate, the trans- yerse constriction appears more distinctly marked, and the region in advance settles back toa slight extent, and inconspicuously invaginates this encircling depression in one or two folds.
Vorticella Conochili, sp. nov., fig. 7.
Body conical-campanulate, soft and changeable in shape. usually somewhat gibbous, one and one-half times as long as broad; trans- versely striate ; peristome slightly narrower than the body centre, the
2u 2
480 . Transactions of the Soctety.
border revolute ; ciliary disc somewhat oblique, not elevated ; posterior extremity attached to the pedicle through the intermedium of a small button-like projection ; pedicle filiform, from seven to eight times as long as the body, only the anterior portion contracting when the foot- stalk is thrown into its small, irregular undulations rather than spiral folds ; contracted body obovate, the button-like extremity invaginate within the body; endoplasm colourless ; nucleus band-like, much curved, often forming an almost complete circle, situated in the anterior body- half. Length of body 1/750 in. Hab. Attached to the gelatinous tubules of Conochilus volvox.
A gathering made in the early part of the month of November contained a large number of the beautiful free-swimming colonial Rotifers Conochilus volvow, and every colony of the many examined bore from three to six individuals of this parasite, or perhaps more properly, commensal Vorticella, the pedicle being attached to the gelatinous material which partially inclosed the colony.
Vorticella molesta, sp. nov.
Body conical-campanulate, less than twice as long as broad, soft and changeable in shape, slightly constricted beneath the peristome, the cuticular surface very finely striate transversely ; peristome ex- ceeding the body centre in width, revolute; pedicle stout, from five to six times as long as the body, the muscular thread becoming rigid and deeply chestnut brown in colour, presumably with age; contracted body broadly obovate, the extremity of the pedicle invaginate. Length of body, 1/575 in. Hab. Attached to the shell of an aquatic snail, probably a young Lymmnea. Social. |
The muscular thread of some species of Vorézcella, notably of V. picta, has been observed to contain many minute scarlet corpuscles, and similar coloured particles have been noticed within or adherent to the contractile filament of other forms; but in the present species the coloration is a deep chestnut brown extending evenly from the point of attachment to the supporting object nearly up to the posterior extremity of the body, gradually fading until the merest trace is visible at the extreme anterior termination. No pedicle has been seen with the colour reaching entirely up to the posterior border of the zooid. The tint also extends to the sheath, but in a much less marked degree. Those pedicles thus affected had lost most of their contractile power, only the proximal, almost colourless portion retaining its ability to coil, an ability exercised imperfectly and apparently with some difficulty. The remaining or tinted region presents the aspect of a slightly undulate, rigid thread, this extended and stiff condition remaining after the separation of the body and the subsequent death of the muscle. The Vorticellz were infesting the shell of the water snail to such an extent as to impede the progress of the mollusc, and to give it the appearance of being surrounded by a whitish fungoid growth.
The transverse cuticular strie are very fine, requiring some manipulation of the mirror to display them distinctly.
New Peritrichous Infusoria, &de. By Dr. A.C. Stokes. 481
Opisthostyla globularis, sp. nov., fig. 8.
Body subglobose, soft and somewhat changeable in shape, often slightly gibbous, the length but little greater than the breadth ; cuticular surface transversely striate; peristome less than the body centre in width, the border revolute; ciliary disc not elevated ; pedicle slightly exceeding the body in length. Length of body 1/000 in. Hab. Pond water, attached to Hydrodictyon utriculatum.
Opisthostyla similis, sp. nov., fig. 9.
Body subvasiform, somewhat changeable in shape posteriorly, less than twice as long as broad, somewhat gibbous, slightly con- stricted beneath the revolute peristome border; the posterior region bearing two rounded, transverse annulations, the anterior being the larger, the posterior extremity often apparently united to the pedicle through the intermedium of a disc-like appendage; cuticular surface strongly striate transversely ; ciliary disc slightly and obliquely elevated ; pedicle in length somewhat exceeding that of the body, the distal extremity scarcely curved ; contracted body obovate, slightly invaginating the extremity of the pedicle. Length of body 1/1125 in. Hab. Pond water, attached to the rootlets of various floating aquatic plants.
This form is readily recognizable from those previously described, by the presence of the annular body-enlargements, and the slight distal curvature of the pedicle. The backward springing of the contracted zooid is that characteristic of the genus, but individuals are at times met with in which the larger, more anterior annulation lacks the usual convex borders, being replaced by flattened, almost perpen- dicular margins, so that this portion of the body more nearly resembles a short cylindrical constriction. In these individuals the posterior ring is frequently inclosed within that part of the posterior region which invaginates the extremity of the pedicle when the zooid is contracted, the animalcule in these cases appearing not to have extended the body entirely so as to free the pedicle wholly from its invagination, the posterior annulation thus becoming obscure or obsolete.
Halsis (adovs, leaping), gen. nov.
Animalcules free-swimming, ovate, persistent in form, peritrichous ; equatorial ciliary girdles two or more; several long, non-vibratile, widely separated setee projecting from the posterior body region ; no supplementary springing hairs; oral aperture terminal, the adoral cilia seeming to form a simple spiral wreath. Inhabiting fresh water.
Halsis furcata, sp. nov.
Body ovate, less than twice as long as broad, the posterior border rounded, the anterior convexly truncate; oral aperture apparently eccentric, surrounded by a short, snout-like projection
482 Transactions of the Society.
followed by a short but conspicuous, curved pharyngeal passage ; equatorial cilia not numerous, forming three girdles, those of the posterior circlet furcate ; caudal hairs long, flexible, distally curved, from six to eight in number, widely separated and arising from the cuticular surface at some distance from the posterior border ; con- tractile vesicle apparently single, spherical], in the anterior body region near one lateral border; nucleus not observed. Movements rotatory on the longitudinal axis, often rapidly backward, with sudden back- ward leaps. Length of body 1/1125 in. Hab. Standing pond water.
. This is undoubtedly a member of the Halteriide of Claparede and Lachmann, but it is refused admission to any described genus by the presence of the setose caudal hairs springing from the posterior body region. These are subequal to the body in length, flexible but non- vibratile, trailing behind when the animalcule is swimming. ‘The creature, however, possesses the ability to throw them forward, and it is probable that the sudden backward leaps and quick turns so often made, are accomplished by the action of these posterior sete. The furcate condition of the cilia composing the posterior equatorial circlet is worthy of notice. ‘The adoral cilia appear to be fimbriated.*
* The original drawing of this animalcule has been mislaid or lost, so that a figure canuot be given.
JOURN.R.MICR.SOC 1889. Pl. X1.
E.C. Knight, ith. West, Newman &Co,imp,
Horaminifera fr om. the London Clay.
x 20
( 483 -)
VIII.—Additional Note on the Foraminifera of the London Clay exposed in the Drainage Works, Piccadilly, London, in 1885.
By C. Davies Saerpory, F.G.S., and Freprerick CHapmay. (Read 8th May, 1889.) Prats XI.
In a former paper on this subject, published in the Journal for 1886, eighty-eight well-marked varieties of Foraminifera were described from the London Clay of Piccadilly, London, thus bringing up the total number of forms recorded from the formation to 136. In the present communication we briefly describe twenty-eight forms, twenty-one of which are new to the London Clay. The fact that one of our former “species” required further consideration and examination led us to manipulate the remainder of samples of the clay collected in 1885, and carefully re-examine our earlier washings, in the hope of finding more specimens worth attention. In this we were successful, and are now enabled to amend our views upon the form previously described as Lagena oviformis, and also to make some interesting additions to our knowledge of the London Clay foraminiferal fauna. All the specimens here described were obtained from the “ black-bed ” referred to at p. 740 of our former paper.
EXPLANATION OF PLATE XI.
Fig. 1.—Wiliolina trigonula (Lamarck). oA eo ae venusta (Karrer). 5 4, 5.—Cornuspira involvens, Reuss. : ss carinata (Costa), 9» 7.—Ammodiscus incertus (d’Orbigny). 5 8.—Haplophragmium agglutinans (d’Orbigny). » 9—Thurammina papillata Brady. », 10.—Textularia agylutinans, var. porrecta Brady. », 11.—Clavulina parisiensis @ Orbiguy. 5, 12.—Chilostomella ovoidea Reuss.
3 La: 9 oviformis Sherborn and Chapman.
», 14.—WNodosaria simplex Silvestri.
pelios 3 radicula, var. annulata Terq. and Berth. 37 LG. 55 fC var. ambigua Neugeboren.
ry slibelliee © ep longiscata d’Orbigny. '
ke! = sp.
5, 20. eS oligotoma Reuss.
Spear Ss5 catenulata Brady.
A obliquata (Batsch).
24,.—Dentulina suleata (Nilsson). » 25.—Vaginulina sp. (? deformed).
» 26. a legumen (Linné), var. » 27.—Marginulina attenuats Neugeboren. » 28 -. costata (Batsch).
5, 29.—Pullenia quinqueloba (Reuss). », 30-32.—Pulvinulina elegans (d’Orbigny). », 33.—Discorbina rugosa (d’Orbigny). »5 34.—Anomalina grosserugosa (Giimbel). All figures are x 20. (‘The specimens will be deposited in the British Museum.)
484 Transactions of the Society.
Miiorina Williamson [1858].
Miliolina trigonula (Lamarck), plate XI. fig. 1. Miltolites tri- gonula Lamarck, Ann. Muséum, vy. (1804) p. 351, No.8; Triloculina trigonula (Lam.) d’Orbigny, Ann. Sci. Nat., vii. (1826) p. 229, No. 1, plate xvi. figs. 5-9; Modéle, No. 93.—Common, but very small; the specimen figured is large in comparison with the others found in the ey Clay. Previously recorded from Sheppey and Haverstock
ull.
Miliolina venusta (Karrer), plate XI. figs. 2,3. Quinqueloculina venusta Karrer, Sitz. k. Ak. Wiss. Wien, lvii. (1868) p. 147, plate ii. fig. 6.—Four individuals. New to the London Clay. Dr. Karrer’s specimens came from the Miocene of Kostej.
Cornuspira Schultze [1854].
Cornuspira involvens (Reuss), plate XI. figs. 4,5. Operculina involvens Reuss, Denkschr. k. Ak. Wiss. Wien, i. (1849) p. 370, plate xly. fig. 20; Cornuspira involvens Reuss, Sitz. k. Ak. Wiss. Wien, xlyiii. 1863, p. 39, plate i. fig. 2—One specimen found by Mr. A. M. Davies in a sample of clay given him by one of us. Previously recorded from the London Clay of Sheppey by Mr. Shrubsole.
Cornuspira carinata (Costa), plate XI. fig. 6. Operculina cari- nata Costa, Atti Acc. Pontan., vil. (1856) p. 209, plate xvi. fig. 15 a, b. -—One individual, which, though damaged, still preserves its characters. This specimen almost exactly corresponds to the form figured by Reuss, from the Septarienthon of Offenbach, as C. Bornemanni, Sitz. k. Ak. Wiss. Wien, xlviii. 1863, p. 39, plate i. fig. 3, which is the same form as C. carinata (Costa). New to the London Clay.
Hapitopuracmium Reuss [1860].
Haplophragmium agglutinans (d’Orbigny), plate XI. fig. 8. Spirolina agglutinans d’Orbigny, Foram. Foss. Vienne, 1846, p. 137, plate vii. figs. 10-12.—One example. New to London Clay.
THuramurna Brady [1879].
Thurammina papillata Brady, plate XI. fig. 9. Brady, Quart. Journ. Mier, Sci, xix. (1879) p. 45, plate v. figs. 4-8.—Not previously recorded from ‘'ertiary beds. Dr. Haeusler* has described numerous varieties from the Jurassic of Switzerland, and Dr. Uhlig + from beds of the same horizon in Austria and Wurtemberg.
Amwmopiscus Reuss [1861].
Ammodiseus incertus (d’Orbigny), plate XI. fig. 7. Opereulina incerta VOrbigny, Foram. Cuba, 1839, p. 71, pl. vi. figs. 16, 17.—
* Neues Jahrb., 1883 (1), p. 60; Annals Mag. Nat. Hist. 5, xi. 1883, p. 262; Quart. Journ. Geol. Soc., xxxix. 1883, p. 27; Neues Jahrb. BB iy. (1), 1885, p. 30. + Neues Jahrb., 1882, p. 152.
On Foraminifera, &c. By C. D. Sherborn & F. Chapman. 485
One specimen. Previously recorded from four localities of the London Clay. (See the former paper, p. 760, Trochammina.)
Textuparia Defrance [1824].
Textularia agglutinans dOrbigny, var., plate XI. fig. 10. DOrbigny, Foram. Cuba, 1839, p. 136, plate i. figs. 17, 18, 82-34. —This variety of 7. agglutinans, with its rounded chambers and subeylindrical form, is comparable with Brady’s var. porrecta (Report, ‘Challenger, 1884, p. 364, plate xlii. fig. 4).
Cravutina d’Orbigny [1826].
Clavulina parisiensis, dOrbigny, plate XI. fig. 11. D’Orbigny, Ann. Sci. Nat., vii. (1826) p. 268, No. 3; Modele, No. 66.—The specimen mentioned at p. 743 of our former paper is here figured, and is the only example found which shows the characteristic triangular shape of the early chambers. Dr. Brady mentions its occurrence in abundance in the London Clay near Clapham Common.*
CHILOSTOMELLA Reuss [1849].
Chilostomella ovoidea Reuss, plate XI. fig. 12. Reuss, Denkschr. k. Ak. Wiss. Wien, i. (1849) p. 380, plate xlviii. fig. 12 a-e——One . specimen. - New to the London Clay.
Chilostomella oviformis Sherborn and Chapman, plate XI. fig. 13. Lagena (Obliquina) oviformis, Sherborn and Chapman, Journ. R. Micros. Soc., ser. 2, vi. 1886, p. 745, plate xiv. figs. 19 a-d.—The erroneous reference of this form to Lagena was principally due to the fact that the interiors of the specimens described were occupied by sand. We have now been so fortunate as to secure a few more specimens which have the internal structure preserved, and we have no hesitation in referring the form to Chilostomella. This is also the opinion of Dr. Brady who has kindly examined our specimens. The interest of this form of Chilostomella lies in the fact that the successive external chamber envelopes the whole of the previous structure, and thus presents what appears to be a test of a single chamber. We givea dotted outline of the internal structure restored from several partially perfect individuals, and have nothing to add to the original description of the exterior.
Noposaria Lamarck [1816].
Nodosaria simplex Silvestri, plate XI. fig. 14. Silvestri, Atti Ace. Gioenia Sci. Nat., vii. (1872) p. 95, plate x1. figs. 268-72.—One small individual. New to the London Clay.
Nodosaria radicula, var. annulata Terquem and Berthelin, plate XI. fig. 15. Glandulina annulata Terg. & Berth., Mém. Soe. Géol. France, sér. 2, x. (1875) Mém. 3, p. 22, plate i. fig. 25.—One example. New to the London Clay.
* Report ‘ Challenger,’ 1884, p. 395.
486 Transactions of the Society.
Nodosaria radicula, var. ambigua Neugeboren, plate XI. fig. 16. Nodosaria ambigua Neugeboren, Denkschr. k. Ak. Wiss. Wien, xil. (1856) p. 71, plate i. figs. 13-16.—Two or three examples. Not previously recorded from the London Clay.
Nodosaria longiscata d’Orbigny, plate XI. figs. 17, 18. D’Orbigny, Foram. Foss. Vienne, 1846, p. 32, plate 1. figs. 10, 11. Nodosaria arundinea Schwager, Sherborn and Chapman, Journ. R. Micros. Soc., ser. 2, vi. (1886) p. 747, plate xiv. figs. 28, 29. Nodosaria longiscata dOrbigny, Brady, Quart. Journ. Geol Soc., xliv. 1888, p. 6.—Since the critical remarks, in our former paper, on d’Orbigny’s figures, Dr. Brady has kindly shown us some of the original specimens examined by dOrbigny, sent to him by Dr. Karrer, of Vienna. We have there- fore had the opportunity of verifying Dr. Brady’s conclusion that d’Orbigny, although he figured only the “sugar-loaf” form, included the whole of these smooth, slender, reed-like Nodosariz in one “species.” Weare much indebted to Dr. Karrer and Dr. Brady for the examination of this form, as the varying conditions of the chambers have unfortunately given rise to almost endless specific naming. Fig. 18 is the particular variety which was named by Terquem N. sublongiscata* ; it shows four chambers, and is unusually perfect compared with the specimens generally found in the London Clay. Fig. 17 is an interesting example, showing the initial chambers.
Nodosaria sp., plate XI. fig. 19—The internal cast of two chambers of a Nodosarian, the upper of which shows fine longitudinal strie.
Nodosaria oligotoma Reuss, plate XI. fig. 20. Reuss, in Geinitz, Paleontographica, xx. part 1 (1872) p. 135, plate xxxii. fig. 16.— One of the numerous varieties of Linné’s Nodosaria raphanus, figured. by Reuss as NV. oligotoma. One specimen. New to the London Clay.
Nodosaria catenulata Brady, plate XI. figs. 21, 22. Brady, Report, ‘ Challenger, 1884, p. 515, plate lxiii. figs. 32-34.—The two fragments figured are all that were found. New to the London Clay.
Nodosaria obliquata (Batsch), plate XI. fig. 28. Nautilus obliquatus Batsch, Sechs Kupfertafeln Conch. Seesandes, 1791, plate 11. figs. 5 a, b,c.—Two fragments only found. New to the London Clay.
Dentatina d’Orbigny [1826].
Dentalina sulcata (Nilsson), plate XI. fig. 24. Nodosaria sul- cata Nilsson, Petrif. Suecana, pt. 1, 1827, p. 33, plate ix. fig. 19.— Only the fragment figured was found. Not previously recorded from the London Clay.
Vaernuuina d’Orbigny [1826].
Vaginulina leqgumen (Linné), var., plate XI. fig. 26. Nautilus legqumen Linné, Syst. Nat., ed. 10, 1758, p. 711, No. 248.—This elegant little specimen we regard as a variety of Linné’s well-charac- terized “ species.”
* Mém. Ac. Imp. Metz, xlii. (1862), p. 487, figs. a, b, in text.
On Foraminifera, de. By C. D. Sherborn & F. Chapman. 487
Vaginulina sp. plate XI. fig. 25.—A small, compressed, and deformed (?) Nodosarian of doubtful relationship.
Marainuxina d’Orbigny [1826].
Marginulina attenuata Neugeboren, plate XI. fig. 27. Neuge- boren, Verh. Mitth. Siebenbiirgen Ver. Nat., Jahrg. ii. (1851) p. 121, plate iv. figs. 3-6.—The name MM. attenuata may reasonably be made to include the whole of the unornamented elongated Marginuline figured by Neugeboren on his plate iv. Indeed, in his later paper (ibid., Jahrg. xi. 1860, p. 55) he has referred three of his former species (M. Orbignyana, M. Reussiana, and M. irregularis) to M. attenuata, thus showing that he did not then agree with the specific value of gradational varieties. Our specimen is the only one found. Not previously noted from the London Clay.
Marginulina costata (Batsch), plate XI. fig. 28. Nautilus (Orthoceras) costatus, Batsch, Sechs Kupfertafeln Conch. Seesandes, 1791, p. 2, plate i. figs. 1 a-g.—Only this specimen found. New to the London Clay.
PuxentA Parker and Jones [1862].
Pullenia quinqueloba (Reuss), plate XI. fig. 29. Nonionina quinqueloba Reuss, Zeitschr. Deutsch. Geol. Ges., iii. (1851) p. 47, plate v. figs 31 a, b—Only one specimen of this slightly compressed form has been found; it shows, however, all the characteristics of Reuss’s variety. New to the London Clay.
Discorpina Parker and Jones [1862].
Discorbina rugosa (d’Orbigny), plate XI. fig. 33. Rosalina rugosa dOrbigny, Foram. Amér. Mérid., 1839, p. 42, plate ii. figs. 12-14.—One specimen, which has lost the final chamber, occurs in the Piccadilly washings. New to the London Clay.
Anomatina d’Orbigny [1826].
Anomalina grosserugosa (Giimbel), plate XI. fig. 834. Trunca- tulina grosserugosa Giimbel, Abh. k.-bay. Ak. Wiss., x. (1868) p. 660, plate un. fig. 104 a, b; Anomalina sp. Sherborn and Chapman, Journ. R. Micros. Soc., ser. 2, vi. (1886) p. 757, fig. 156.—Having found more specimens of this form, we are able to assign it definitely to Giimbel’s “species,” according to the suggestion expressed in our former paper.
Punyinuuina Parker and Jones [1862].
Pulvinulina elegans (d’Orbigny), plate XI. figs. 30-32. Rotalia (Turbinulina) elegans @Orbigny, Ann. Sci. Nat., vii. (1826) p. 276, No. 54; Pulvinulina elegans (d’Orbigny), Brady, Report ‘ Challenger,’
488 Transactions of the Society.
ix. (1884) p. 699, plate cv. figs. 3 a, b, c—Numerous small specimens of this form, which, according to Parker, Jones, and Brady,* passes insensibly into P. Partschiana d’Orbigny, occur in our last washings. It has previously been recorded by Professors Rupert Jones and Parker from the London Clay of the bed of the Thames at Chelsea, and from Wimbledon.
* The Pulvinulina elegans group, including P. Partschiana, were fully treated of by Parker and Jones in 1865, Phil. Trans., clv. pp. 392, 393, 397, pl. xvi. figs. 44-46.
( 489 )
SUMMARY
OF CURRENT RESEARCHES RELATING TO
ZOq LOG Ys AND. BOT ANY (principally Invertebrata and Cryptogamia), -
MICROSCOPY, &c., INCLUDING ORIGINAL COMMUNICATIONS FROM FELLOWS AND OTHERS.*
ZOOLOGY. A. VERTEBRATA :—Embryology, Histology, and General. a. Embryology.t+
Uterus and Embryo.{—Mr. C. 8. Minot has investigated the relations of the uterus and embryo in the Rabbit and in Man. In the resting uterus of the rabbit there are six longitudinal folds; the ovum attaches itself on or between the two folds nearest the mesentery, and the placenta is then developed ; the two adjacent lateral folds form a cushion (“ peri- placenta”) about the placenta, but the two folds opposite the mesentery are flattened out by the stretching of the walls to form the swelling to contain the embryo; they constitute the ob-placenta. The entire epithelium lining the uterine swelling degenerates, and this degeneration affects the glands also. The connective tissue increases by hyperplasia in the peri- placenta and to a greater degree in the placenta, and is transformed for the most part into uninucleate perivascular decidual cells, but also in part into large multinucleate cells. In the placental region the glands are preserved as irregular anastomosing rows of coarse granular matter ; below the glands is a zone containing wide vessels and large multi- nucleate cells.
The embryo is attached at first to the surface of the placenta only by the ectoderm, with which the mesoderm soon becomes connected. So soon as the ccelomatic fissure appears we can speak of a foetal chorion adhering to the placenta. When the allantois grows out it forms the stalk of connection between the embryo and the placental chorion. Outgrowths of the chorion penetrate the glandular layer of the placenta. The ccelom of the embryo does not extend to the edge of the placenta next the peri-placenta, but the mesoderm does and is covered by ectoderm.
In the ob-placenta degeneration and resorption affect only the surface epithelium and the upper part of the glands; the deep portions
* The Society are not intended to be denoted by the editorial “ we,” and they do not hold themselves responsible for the views of the authors of the papers noted, nor for any claim to novelty or otherwise made by them. The object of this part of the Journal is to present a summary of the papers as actually published, and to describe and illustrate Instruments, Apparatus, &c., which are either new or have not been previously described in this country.
+ This section includes not only papers relating to Embryology properly so called, but also those dealing with Evolution, Development, and Reproduction, and allied subjects. t Journal of Morphology, ii. (1889) pp. 341-462 (4 pls.).
490 - SUMMARY OF CURRENT RESEARCHES RELATING TO
remain as a series of shallow cups, having been stretched transversely by the expansion of the ob-placenta. The epithelium of the cups unites into a new continuous layer, the glands grow up into follicles and are again stretched out by the expansion of the walls. The ectoderm which attaches the embryo disappears from the surface of the placenta during the eleventh day ; the vascular connective tissue of the allantois probably grows by forming true villi into the placenta, and so comes close to the maternal circulation.
The observations on the human subject are, as may be supposed, somewhat scattered. ‘The author finds that the umbilical cord is not covered by the amnion, but by an extension of the foetal epidermis. Its coelomatic cavity is completely obliterated during the third month, and a little later the stalk of the yolk-sac is resorbed. The allantoic epithelium persists as a tube or cord of cells for a long period. The blood-vessels have specialized walls derived from the surrounding mesoderm, but have no true adventitia. Connective-tissue fibres begin to develope during the third month. The amnion is covered by a single layer of ectodermal cells, which are connected by conspicuous inter- cellular bridges; it- has no true stomata. The chorion consists of two layers, mesoderm and ectoderm, both of which are present over all parts of the chorion during the entire period of pregnancy. The mesoderm has at first a dense colourable matrix, with cells, which colour very slightly. During the second month the matrix loses its colouring pro- perty, and subsequently the cells acquire a greater affinity for colouring matters. The matrix assumes a fibrous appearance, and in one region the mesoderm is differentiated into an outer fibrillar layer and an inner and thicker stroma-layer. During the first month the ectoderm divides into an outer dense protoplasmic layer and an inner less dense cellular layer. In the later stages of pregnancy the whole ectoderm of the smooth chorion acquires the character of the cellular layer, except near the margin of the placenta. The villi are at first of awkward and irregular form, but their branching gradually becomes more regular, and the twigs acquire a slender and more uniform shape.
The menstruating uterus is characterized by hyperemia, by hyper- plasia of the connective tissue of the mucosa, and by hypertrophy of the uterine glands; the upper fourth of the mucosa is loosened and breaks off, but there are no decidual cells. The changes of the uterus during menstruation and gest.tion are homologous, the menstrual cycle being prolonged and modified by pregnancy ; hence it is that conception takes place only at the menstrual period, for the ovum can only modify the menstrual change, not initiate the formation of a decidua. No satisfactory explanation of the origin of the amnion has yet been offered. The placenta is an organ of the chorion, but we possess no positive information as to how it performs its nutrient functions.
Fecundation and Segmentation of Ova of Rats.*—Professor A. Tafani has observed four stages in the maturation of non-fertilized ova of rats. In some the maturation-spindle extends under the surface, while in others it is directed towards a point of this surface, which it raises up. In some one, and in others two polar globules may be seen to be expelled. Fecundation takes place when the female pro- nucleus is on the point of being formed. Not more than one spermatozoon
* Arch, Ital. Biol., xi. (1889) pp. 112-7.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 491
has been seen to come into contact with the egg; its head, which is at first homogeneous, soon becomes resolved into a small thread formed of chromatic granules which are connected with one another by filaments, just as in the case of Ascaris megalocephala, as described by Van Beneden. The mode of union of the two pronuclei is carefully described. The segmentation-nucleus is comparatively large. The first plane of segmentation passes through one of the meridians of the egg, and the first two blastomeres are exactly equal and similar; it will be remembered that this is not the case in the Rabbit. When there are eight blastomeres they are all equal, but exhibit a tendency to become arranged in two distinct groups. When there are twelve blastomeres four are larger than the rest.
Reproduction and Development of Teleostean Fishes.*—Mr. J. T. Cunningham gives an account of his observations on the ova of Teleostean fishes, made at the new Marine Biological Laboratory at Plymouth. The Common Sole was found to spawn in March, April, and May; the ovum after extrusion is of considerable size, about 1:5 mm. in diameter, It is distinguished by having an immense number of oil-globules of very small size; these are arranged in groups of irregular shape ; another characteristic is that the yolk is not perfectly continuous and homo- geneous, but coextensive with the blastoderm there is a single superficial layer of separate yolk-masses ; this layer extends with the blastoderm, so that when the latter has enveloped the yolk the layer of yolk-segments also envelopes it completely, forming a superficial layer over the whole surface of the yolk. These peculiarities enable the sole’s egg to be easily recognized when taken on the open sea in the tow-net. Mullus and Solea are the only genera whose ova have undoubtedly the peripheral layer of yolk-segments. It is interesting to notice that these ova present a condition of the yolk intermediate between that characteristic of non- pelagic ova and that seen in typical pelagic ova. It is possible that the peculiar character of the ovum of Solea indicates that there is no close affinity between this genus and Pleuronectes.
After describing a number of ova and his experiments with them, Mr. Cunningham propounds a hypothesis concerning oil-globules in pelagic teleostean ova. He finds that whenever the adult has a large quantity of oil in its tissues, the ova possess one or more oil-globules in the yolk. It is probable that the excess of oil in the tissues of the parents extends into the ovum, and during the developmeut of the _ latter supplies the embryo with an abundance of fat which is necessary to its constitution. The cause of many ova which are provided with oil globules having a greater specific gravity than those that are without them must be explained by. the greater density of their protoplasin and yolk.
In conclusion, there is a note on the development of the vascular system and ccelom in pelagic ova of Teleostei. In a great many the heart, at the time of hatching, consists of a tube which opens posteriorly out of a wide space between the yolk, while the heart itself is surrounded by another cavity separated from the just mentioned space by a thin membrane ; the cavity which communicates with the heart exists, at an earlier stage, as a.space between the epiblast of the anterior part of the yolk-sac and the periblast; traced back it is found to be nothing more
* Journal Marine Biol. Assoc., i. (1889) pp. 10-54 (6 pls.).
4992, SUMMARY OF CURRENT RESEARCHES RELATING TO
nor less than the segmentation cavity. The space surrounding the heart is a portion of the true celom. The heart is produced by the formation of the central mesoblastic cells into a tube which, as soon as it has a lumen, communicates with the space between the ventral epiblastic body- wall and the periblast. The cavity in which it is contained is due to a splitting of the mesoblast.
The interesting morphological peculiarity about the venous sinus in the Teleostean embryo is that it is the persistent segmentation cavity. This may partially disappear owing to the contact of its walls, but it is not obliterated by the growth of the mesoblast, so that, when the sinus venosus appears, it is not as a cavity or system of veins entirely sur- rounded by splanchnic mesoblast, but is the old segmentation cavity between the epiblastic ventral wall of the yolk-sac and the periblast. At a later stage, no doubt, the sinus venosus acquires mesoblastic walls all round it, but this is not till the yolk has been absorbed.
8. Histology.*
Vital Processes in Living Cells.;—Prof. C. Frommann has made a study of the vital processes in living cells. He commences with an account of ripe unfertilized and fertilized ova of Strongylocentrotus lividus. The granules found in the protoplasm are connected partly by very fine and partly by somewhat coarse and short filaments. The processes between the granules lead to the formation of extremely fine or some- what goarser plexuses. The radiate marking which is seen in the periphery of some eggs is due partly to rather long fine filaments, which are beset with separate granules or with small spindle-shaped nodules, and partly by somewhat coarser indistinctly granulated cords which are connected by processes with their neighbours ; they sometimes take a zigzag course.
All the formed parts of the egg undergo a constant change of form and size as well as some alteration in their refractive power ; they fuse with one another or divide into two or more fragments; they disappear, while others are freshly formed; and all these processes occur so rapidly that it is quite impossible to figure all the successive images that are presented. These alterations may, moreover, occur in the most varied manner. Coarser filaments may break up into distinct granules which separate from or unite with one another; others become indistinctly granulated or disappear altogether. These processes are often preceded by a division of the filaments into two cr more pieces, which may under- go various kinds of changes. Changes in form may accompany alterations in the characters of the filaments, and they may become bent, hoop- shaped, or united by bonds with their neighbours. Coarser granules exhibit corresponding structures.
The same kind of changes in the yolk-substance are seen in fertilized as well as in unfertilized egos, and there can be no doubt that, so far as its vital changes are concerned, the yolk-mass completely corresponds to the protoplasm of other cells.
The rounded or oval homogeneous egg-nucleus has a boundary which alters in character; there is often a delicate, pale, and unbroken contour which may yield to one which is delicately granular or
* This section is limited to papers relating to Cells and Fibres. + Jenaische Zeitschr. f. Naturwiss , xxiii. (1889) pp. 389-412 (1 pl.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 493
filamentous, and which may project into the nucleus and give its boundaries an irregular appearance. After treatment with 0-2 per cent. chromic acid the nucleus generally retains sharp and refractive contours, while at the same time the nucleolus becomes distinctly apparent.
The much discussed question of the radiate figures in the fertilized egg is next considered. The author does not find that they exhibit the regularity which we should be led to expect from the figures and de- scriptions of O. Hertwig, Fol, and Flemming; as in the other parts of the cell-body, there are changes in these parts. The rays as well as their constituent parts continually alter their form and character, dis- appear, and are again built up; these changes are described in some detail.
In embryos with from twelve to sixteen and more cells the spaces between the separate cells are generally very slight; in these granules may be detected, which may possibly be cell-bridges which appear as granules in consequence of their shortness. When the intercellular spaces are somewhat wider there are some indications of filaments.
The changes which take place in the network of the grey substance of the brain of Torpedo marmorata and Raja asterias, and in the gan- glionic cells of the Torpedo, are next considered. The changes which take place in the stroma of the ganglionic cells have the same character as those which occur in the grey substance—and but for their being slower—as what are seen in the eggs of Strongylocentrotus lividus. They also correspond in their morphological relations with what he. been observed in the blood-corpuscles of Invertebrates, the network of the tentacles of Hydra, and the living cartilage-cells of the rabbit. In the leucocytes of the frog not only do the nuclei disappear, and be again formed from protoplasmic parts, but changes may take place in the granular and filamentar parts of the cell-body without any new formation of nuciei. Similar examples may be cited from many plants.
New Formation of Cells.*—Dr. B. Morpurgo finds that new cella are formed by indirect fission, even during acute inanition of the organism. Karyokinetic figures are found both in growing organs and in the adult organs of animals that have died of hunger, and, therefore, in organs where they give signs of a formative process as well as where they represent cellular regeneration. Indirect fission, under whatever conditions produced, becomes less active when there is an inanition of the organism. The numerical diminution of mitoses is relatively less in slightly differentiated glandular cells and in investing epithelia than in highly differentiated glands; of these latter we may say that the process of karyokinesis is almost wholly limited to the period of their more active growth. Of the differentiated organs, the gonads alone ex- hibited a process of very active karyokinesis during the inanition of the organism. This shows that these organs are highly individualized even in animals which are high in the zoological scale, and that they are able to demand of other organs the sacrifice of a richly nutrient material.
Relation between Cell-body and Nucleus.;—Dr. F. Tangl comes to the conclusion that the sharp boundary between the nucleus and the cell-body disappears when the achromatic nuclear membrane is de-
* Arch. Ital. Biol., xi. (1889) pp. 118-33. + Math. u. Naturwiss. Bericht. aus Ungarn, vi. (1889) pp. 61-77 (1 pl.).
1889. 2M
494 SUMMARY OF CURRENT .RESEARCHES RELATING TO
stroyed, and that it does not reappear until a new membrane is formed around the daughter-figures. During mitosis there is a much closer connection between cell-body and nucleus than when the nuclei are at rest; this is probably due to the intermixture of the nuclear material with the interfilar mass. Particular attention is directed to the influence of preservative reagents on the characters of the cell.
Nerve-cells in Birds.*—Sig. E. Falzacappa has investigated the origin of the nerve-cells and the minute structure of the central nervous system in birds. His observations led him to the following conclu- sions:—(1) there is in the embryonic state an entire absence of the polygonal nerve-cells, but the primordial cells are identical with those of the neuroglia of the adult; (2) cells arise from the primitive elements by gemmation, after the fashion of a Nostoc chain; (3) these new cells are gradually transformed into the free polygonal elements; (4) the nuclei of the primordial cells resemble those of the adult neuroglia ; (5) the primitive cells furthermore respond to reagents in the same way as the neuroglia or the perfect polygonal cells. ‘The primordial cells of the embryonic brain are therefore neurogenetic, giving rise to the special nerve-cells. The author proceeds to bring forward detailed histological evidence in support of the conclusion that the specific nerve-cells have the same nature as those of the neuroglia. Plates are promised in a completed memoir,
Form and Size of Red Blood-corpuscles of Adult and Larval Lampreys.{—Mr. 8. H. Gage has examined the red blood-corpuscles of the lampreys of Cayuga Lake. The varying statements made with regard to these cells give an interest to his observations. Wagner, in 1838, described the circular outline of these cells, and he, with Kéllker and others, have noted their biconcave character. Gulliver and Gunther state that they are flat or biconvex, and neither Gegenbaur nor Wieders- heim draw attention to their peculiarities; Shipley and Thompson have asserted that the blood-corpuscles of the larvee were oval and of the adult circular. Mr. Gage finds that the red blood-corpuscles of both adult and larval lampreys are circular, biconcave, nucleated discs; the observation that they run into rouleaux, like those of all Mammals, except the Camelide, appears to be new.
y. General.
Fresh-water Fauna of East Africa.{—Dr. F. Stuhlmann has a pre- liminary report on his investigation of the fresh-water fauna of East Africa. The Ostracoda are well represented, both by species and indi- viduals, and there appear to be some very remarkable forms among them. The Oligochzeta—Perionyx, Eudrilus, and Digaster—are very numerous; there are several species of Nais, and a large number of Dero; a new species of Aolosoma was found in enormous quantities. Turbellarians appear to be scarce. Of Nematodes some small forms of Rhabditis are reported. Conochilus volvox is very common. A small clear greyish- green Hydra with five arms was observed. The Protozoa are very numerous, there being quite a series of Rhizopods, several species of Vorticella, &c., and a number of Flagellata.
* Bull. Soc. Nat. Napoli, ii. (1888) pp. 185-93. + Proc. Amer. Soc. Micr., x. (1888) pp. 77-83. ¢ SB. K. Akad. Wiss. Berlin, 1888, pp. 1255-69.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 495
B. INVERTEBRATA,
Lymphatic Glands of Cephalopods and Decapodous Crustacea.*— M. L. Cuénot considers that the organ in Cephalopods which Férussac and d’Orbigny regarded as the pellicular appendage of the auricle, and Owen as the homologue of the second branchial heart of Nautilus, is a - lymphatic gland. He describes it as being bounded externally by a thick epithelial layer; its cavity is traversed by a complicated network of connective tissue, in the meshes of which there are a number of nuclei and of cells which exhibit the peculiar mode of development of lymphatic cells; that is to say, whose nuclei become gradually surrounded by refractive granules, which form the characteristic and constant con- tents of amcebocytes. In the decapodous Crustacea there are two sets of lymphatic glands; the first and most important (and, above all, the most constant) is situated in the gill between the efferent and afferent vessel ; the other may be seen in a Crab by carefully raising the dorsal carapace and removing the cuticular matrix ; to the latter it adheres strongly. It begins a little below the heart on either side of the middle line and terminates at the level of the last pair of thoracic appendages; each of these glands has the form of an elongated pouch, which is slightly con- tractile and communicates freely with subjacent venous lacune. In section it is seen to be bounded externally by the chitinogenous matrix ; there then comes a zone of irregularly disposed muscular fibres, and then a network of connective fibres, in the cavities of which there are a number of nuclei and cells. The contents of a living gland were found to consist of a considerable number of mature amcebocytes, filled with refractive granules and developing nuclei, mixed with numerous reserve- ‘products. In the Brachyura these organs appear to be easily seen; among the Macroura they have been found active in Pagurus striatus and Hupagurus Prideauxi, but greatly reduced in Galathea strigosa and the Spiny Lobster.
Mollusca. a. Cephalopoda-
Structure of Siphon and Funnel of Nautilus Pompilius.t—Mr. H. Brooks has some preliminary remarks on this subject. ‘The siphon com- mences in the first chamber as a cecum, the closed end resting against the inner surface of the apex of the shell; it consists of a series of tubular sections extending from septum to septum, and increasing in -diameter as the chambers expand. Each section is made up of an outer calcareous sheath, and an inner tube of conchiolin. In the outer sheath there are spicules which overlie one another, and are arranged in such a way as to form an exceedingly porous structure; the spicules are fusiform, and are, as a rule, arranged in stellate figures; those that ex- tend beyond the outer surface of the sheaths often end in irregular knobs, many of which have the appearance of chestnut burrs. In very young siphons, the sheaths are made up of slender threads, placed in the same way as the spicules of the older sheaths, The spicules are made up of slender transparent sticks of calcareous matter, which are held together in bundles by organic matter. There seems to be a well-marked period in the growth of the siphons when they first commence to form spicules, but this, as yet, has not been exactly determined.
* Comptes Rendus, eviii. (1889) pp. 863-5. + Proc. Boston Soc, Nat. Hist., xxiii. (1888) pp. 380-2 (2 pls.). 2m 2
496 SUMMARY OF CURRENT RESEARCHES RELATING TO
The conchiolin tube commences as a closed sac fitting into the sheath of the apical chamber ; it extends unchanged in thickness through the first funnel; from the second to the fourth septum the tubes are much attenuated. At about the fifth, the tubes no longer pass through the funnels, but become disconnected. The older funnels are made up of five layers:—(1) an outer layer formed by the anterior end of a posterior sheath, where it embraces the funnel ; (2) a darker and denser layer than the outer layer which contains more organic matter; (&) the shell layer of the funnel proper; (4) the dense layer forming the anterior end of an anterior spicular sheath ; and (5) an inner layer that is extremely short, and reduces the opening of the funnel at its posterior end. The last two layers are not present in the funnel of the living chamber.
So-called Organ of Verrill in Cephalopoda.*—Dr. J. Brock points out that the so-called organ of Verrill in Cephalopods was discovered and described by Heinrich Miller more than thirty years ago, while Bebretzky has made some observations on its development. The recent statement of Mr. Laurie that the organ is absent from the adult Loligo and Ommastrephes is probably due to the fact that preserved material only was examined; Miiller himself was aware that the funnel-organ was completely destroyed by the ordinary preservative fluids. The organ, indeed, has been seen in so many Cephalopods that it may well be said to be found in the class as such. The author confirms the account given by Miiller as against the discrepant description of Laurie.
B. Pteropoda.
Morphology of Spinous Sacs of Gymnosomatous Pteropoda.t—Dr. P. Pelseneer objects to the view recently enunciated by P. Schalfejeff as to the homology of the “sacs 4 crochets” with any part of the arms of Cephalopoda. These arms and the organs which they carry are entirely pedal in nature, while the sacs of all the Gymnosomata are inserted on the internal wall of the buccal cavity. As the Aplysina have the greatest affinities to the Gymnosomata they should be examined when it is sought to explain the nature of the sacs; now, in Notarchus the buccal cavity is lined by spinous hooks, and those found in the Pteropods are only specializations of the spinous palatine vault of Notarchus. It is to be noted that the sacs are not always as long as in Clione or Pnewmodermon ; in Dexiobranchza, which is the most primitive of existing Gymnosomata, and in Clionopsis they only form slight depressions in which the hooks are implanted.
y. Gastropoda.
Ventral Nervous Mass of Fissurella.s—Dr. L. Boutan deals with some criticisms of Dr. B. Haller. That author has asserted that the ventral nervous mass forms a homogeneous centre in which two distinct portions cannot be made out ; and that the centre is single. Dr. Boutan declares that this is not the case, for two centres may be fused histolo- gically, and yet be distinct morphologically, and this is the case with Fissurella and a number of other Molluscs.
* Nachrich. K. Gesell. Gottingen, 1888, pp. 476-8. + See this Journal, 1888, p. 932. t Zool. Anzeig., xii. (1889) pp. 312-4. § Arch. Zool, Exper, et Gén., vi. (1888) pp. 375-421 (8 pls.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 497
The study of a series of sections shows that the histological separation of the centres is not more marked in the upper part of the nervous mass, where authors seem to agree in recognizing the presence of pedal ganglia and the first two asymmetrical ganglia, than in the lower part of the neryous mass. The study of larve shows that the ventral mass is certainly formed of two distinct nerve-centres (first two asymmetrical ganglia and pedal ganglia). If it is impossible to establish a histological distinction between the two centres, on account of the continuity of the layer of peripheral nerve-cells, it is quite easy to distinguish in the nervous mass, by the aid of the groove and of the two orders of nerves, what part belongs to either of the fused centres. An examination of sections shows that the general form of the four ganglia which serve to form the nervous mass as a whole, is that of four cylinders united by pairs, and closely applied to one another by one of their faces. The structure of the epipodium and the close relations which it has with the mantle in the young Fissurella should lead us to regard it as part of the mantle, and to keep for it the name of inferior mantle.
Descent of Ova in Helix.*—M. J. Pérez has investigated the descent of the ova in the canal of the hermaphrodite gland of Helix. At what- ever season the efferent canal is examined, the inferior part of the tube is always found filled with sperm. It is evident that the ova must pass through the efferent canal a short time before they are found in the diverticulum. The author has dissected a large number of specimens day by day. He found in some that the canal was less distended by sperm than usual, and had a peculiar greyish appearance. Microscopic examination of the contents showed that the sperm was more or less completely altered, and that the epithelium of the efferent canal was also being destroyed. When the sperm and epithelium are both completely absorbed, the efferent canal is empty and the way is open for the ova. The author has not yct been able to observe their passage directly, and thinks it is effected in a very short time.
Anatomy of Clione limacina.t—Herr P. Schalfejeff commences by directing attention to the so-called jaws of this mollusc. The walls of the sheath are formed of a thick layer of circular muscles covered by a very thin investment of connective tissue. When at rest the jaws have, externally, a layer of longitudinal muscles, part of which forms the retractor of the seizing apparatus ; the spaces between the muscles contain connective substance which forms a thick layer of fibrous appearance, a cylindrical epithelium, and an armature of hooks which is connected with the epithelium. The hooks consist of a horny substance which is not chitin, and rests on giant-cells, the finely granular protoplasm of which fills up the hollow of the tooth, as far as its tip. Similar characters have been observed in Pnewmodermon.
As to the connection between the organ of Bojanus and the pericardial cavity, the author affirms that there is not merely an opening, but a typical funnel; the epithelium of this, which is characterized by very long flagella, passes on the one side into the very flat epithelium which covers the inner surface of the pericardial cavity, and on the other into the glandular epithelium of the kidney.
* Comptes Rendus, eviii. (1889) pp. 365-7. + Zool. Anzeig., xii. (1889) pp. 188-90.
A498 SUMMARY OF CURRENT RESEARCHES RELATING TO
Reproductive Organs of Valvata piscinalis.*— Dr. P. Garnault gives a description of the reproductive organs of Valvata piscinalis ; at first sight they appear to differ a good deal from those of other andro- gynous Molluscs, but the resemblances are seen when the relations of the parts are laid down as in a ground-plan. At the same time they are distinguished by the fact that there is a communication between the efferent canal and the copulatory pouch, and this ensures self-fecundation in cases in which copulation is not effected. Further details and illustrative figures are promised.
5. Lamellibranchiata.
Morphology of Teredo.t—M. A. Ménégaux has investigated the homologies of the different organs of this aberrant Lamellibranch. Having discovered the anterior adductor-muscle, he is able to say that it is a dimyarian; this muscle is very small, is covered by a pallial lobule and separated from the posterior adductor by the rectum and a vessel which accompanies it. The “ palettes” are moved by three special muscles, the largest of which arises from the siphonal muscles, the other two are lost in the mantle. The single aorta corresponds anteriorly with the anterior and posterior aorte of other Lamellibranchs, but after it has passed the posterior adductor it no longer corresponds to the posterior aorta. To the right of the rectum it gives off two lateral pallial vessels ; then it passes slightly to the right, follows the right siphonal nerve and gives off a branch to each of the siphons. This asymmetry of the circu- latory system is more apparent than real; it reminds one of what obtains in Pholas, and the difference is due to the fact that the mantle of Teredo being greatly developed in a longitudinal direction the posterior aorta is of considorable length before it bifurcates to go to the siphons.
Origin of Unionide.{—Prof. M. Neumayr has no doubt that the great stock of the Mollusca was originally developed in the sea. Of the fresh-water groups now existing, the most widely distributed and important of the Lamellibranchs are the Unionide, which appear to be descended from the marine Trigonia. 'This form has the hinge of the peculiar schizodont type, and, though the hinge-structure is exceedingly variable in the Unionide, we find on close examination of normal forms that they may be referred to the same type. Affinity is also shown by the structure of the gills, the separation of the two lobes of the mantle, and the absence of siphons. In both groups the nacreous shell exhibits extraordinary development, there is a strong epidermis and a resemblance in the arrangement of the muscular scars. It is particularly remarkable that in many geologically young Uniones of Pliocene and recent times shell-ornaments appear as retrogressive structures, such as occur else- where only in the Trigoniz.
Molluscoida. a, Tunicata.
Developmental History of Distaplia magnilarva.§—In the first of his memoirs on the development of this compound Ascidian, Dr. M. v. Davidoff deals with the maturation of the egg. The structure which is
* Zool. Anzcig., xii. (1889) pp. 266-9.
+ Comptes Rendus, eviii. (1889) pp. 537-8.
t Anzeig. K. Akad. Wiss. Wien, 1889, p. 4; Ann. and Mag. Nat. Hist., iii. (1889) p. 372. § Mittheil. Zool. Stat. Neapel, ix. (1889) pp. 113-78 (2 pls.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 499
generally known as the egg in Ascidians is not what is ordinarily regarded as such; it is rather an ooblast which produces eggs, and it is consequently comparable to the ooblast of the Appendicularia (Fritillaria). The eggs produced by the ooblast function as such in the Appendicularia, while in Ascidians only one is capable of fertilization; all the rest become aborted and may be spoken of as testa-cells. The nuclei of all the eggs arise as buds of the nucleus of the ooblast or karyoblast. In Ascidians they are formed as simple constrictions of parts of the membrane and reticulum of the karyoblast, without the intervention of the nucleolus. On the surface of the ooblast of Distaplia they increase karyokinetically. Later on the muscular buds or nucleogemme become surrounded by part of the protoplasm of the ooblast; and thus become cells, and separate from the ooblast. The eggs of the Appendicularia retain, on constriction, a follicular investment, with which the complex of ooblasts of these animals is from the first surrounded. In Ascidians the abortive eggs do not retain any covering, but lie in the space between the egg and the follicular epithelium.
There is reason to suppose that the reduction of the eggs formed by the ooblast goes still further than is the case in Ascidians. The nucleo- gemme lose their specific protoplasmic covering and become lost in the ooblast. The various phenomena of formation of buds of the karyoblast which have been several times observed in Vertebrates are probably of the same character. In later stages of cleavage it may be seen that some of the abortive eggs of Distaplia are entirely the large endublast cells, while others remain for some time without taking any part in forming the tissues of the larva. When the abortive eggs have left the ooblast the latter forms a true egg. All the protoplasm of the egg breaks up into yolk-bodies in such a way that no intermediate substance is retained. At the same time the membrane and reticulum of the germinal vesicle become lost in its karyoplasm and are converted into a plasmatic, actively moving, amceboid body, which gradually extends itself in a plexiform fashion in the whole egg (ergoplasm). The nucleolus, which has till now remained passive, is converted by internal histo- logical differentiation into a “polar nucleus” with membrane, nuclear network, and nucleolus. By the action of the ergoplasm the polar nucleus is conveyed to the periphery of the egg; it loses its membrane and network, its chromatin becoming converted into chromatic loops, which give rise to a chromatic figure when the polar globule is con- - stricted off. It behaves therefore just as the germinal vesicle is known to do. The formation of one polar globule was observed, and this must be regarded as cell-division. JBiitschli’s hypothesis that the polar globules are rudimentary eggs is so far supported by what obtains in Distaplia where the abortive eggs are all of the same size after their division. The cleavage nucleus is surrounded by a large quantity of ergoplasm ; when observed it was found to consist of a large number of similar merites. The ergoplasm is to be identified with the protoplasm of Kuppfer.
8. Bryozoa.
Anatomy of an Arenaceous Polyzoon.*—Mr. A. Dendy describes a remarkable new genus of ctenostomatous Polyzoa, found near Port Phillip Head, which he calls Cryptozoon, and of which two species, C. wilsoni and
* Royal Soe. of Victoria, 1889, 8vo, 11 pp. and 3 pls,
500 SUMMARY OF CURRENT RESEARCHES RELATING TO
C. concretum, have been distinguished. The organism forms tubular, chitinous zocecia enveloped in common aggregations of sand; the poly- pides are provided with a muscular gizzard containing two horny teeth. The chief difficulties in the way of the study of the soft tissues consist in the very minute size of the individual polypides, and in the difficulty experienced in separating them from the mass of sand-grains in which they are enveloped and to which the zocecia firmly adhere.
The ccencecium is dichotomously branched and the branches come off in several planes; it consists primarily of a slender chitinous tube; the whole is divisible into what may be termed nodes and internodes; the former are dense aggregations of grains of sand firmly held together by the chitinous zocecia, while the latter are longer or shorter, slender, chitinous tubes connecting the nodes together. It is to be especially noted that the tubular internodes are not continuous through the substance of the sandy nodes, but each, on entering the sandy mass, breaks up into a kind of rete mirabile, formed chiefly of the delicate tubular Zocecia. The zocecia are very delicate, and it is possible that, in Cryptozoon, as in those horny sponges which take on an arenaceous habit, the chitinous portion of the skeleton is actually reduced in con- sequence of the addition of the sand, which may be considered as supplementing, and, possibly, to a certain extent replacing the chitin. The wall of each internode appears in optical longitudinal section to be clothed internally with a deeply staining epithelium, the cells of which secrete the chitinous wall of the tube; this lining is, no doubt, a direct continuation of the ccelomic epithelium of the polypides, and appears to be the only organic connection between the different members of the colony.
So much of the anatomy of the polypide as could be made out is described. The epithelium of the tentacles does not present the same character over the whole surface; on the inturned face of each tentacle there are two parallel longitudinal rows of small, columnar cells, each of which contains a relatively large, deeply staining nucleus. The cilia on the tentacle are nearly as long as the tentacle is thick, and they always move in a perfectly definite and regular manner. The alimentary canal is very complex, and five distinct parts—pharynx, cesophagus, gizzard, stomach, and intestine—can be recognized in it.
The gizzard is globular in shape, and has thick muscular walls, con- sisting mainly of a stout circular band of muscles oval in section, and composed of a great number of delicate fibres, surrounding two relatively large chitinous teeth. These last are squarish in shape, and flattened. The stomach is very large, elongated and saccular, and is differentiated by the character of its lining membrane into two totally distinct regions—- an upper, non-digestive, and a lower, digestive portion. The entire ali- mentary canal is clothed externally by a delicate, closely-fitting, flattened epithelium, the nuclei of which are plainly discernible over the greater part of its surface. The muscular system is well developed.
The author remarks that it is interesting to find a Polyzoon acquiring a habit with which we are already familiar in other groups, such as Foraminifera, Sponges, and Annelids. The genus is obviously closely allied to Bowerbankia, from which it differs most markedly in the habit of agglomerating particles of sand on to the zoccia. In conclusion, the distinctive characters of the new species are briefly enumerated.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 501
Structure and Metamorphosis of Larva of Flustrella hispida.*— M. H. Prouho has made a study of the larva of this Bryozoon. In the oral region there is a pyriform organ with a vibratile plume and a sucker, and in the aboral region an ectodermic pad ; the two regions are separated by a ciliated corona. In addition to these there is an internal hollow organ, the cavity of which communicates with the exterior by an orifice on the oral surface between the pyriform body and the sucker ; it may be regarded as an embryonic digestive sac. As the larva approaches the free stage the walls of the sac become less and less distinct, and are finally absorbed. In this point the free larva differs essentially from Cyphonautes, in which, as all agree, there is a digestive tube. The ectoderm and mesoderm become considerably differentiated in the free larva. A bundle of nerve-fibres, with which are connected some unipolar cells, directly connects the pyriform organ with the aboral pad. Some of these fibres extend as far as the vibratile plume and make their way between the glandular cells of the pyriform body, while a right and a left bundle become detached to furnish fibres to the ciliated cells of the groove, to those of the corona, and to the very numerous vibratile swel- lings which are scattered over the dorsal surface. Asall the ciliated cells of the larva are connected with the aboral ectodermic pad, and as this is provided with rigid cilia, it appears to be justifiable to regard it as having a sensory function.
On each side of the larva there are parietal muscles comparable to those of the adult, and longitudinal muscles, which are adductors of the valves, traverse the middle of the larva. The most interesting meso- dermal structure, and one which has not yet been noticed in the larve of marine ectoproctous Bryozoa, is a subepidermic cellular layer which is particularly developed in the aboral region.
When the larva becomes fixed the corona is folded inwards, and the sucking plate fuses with the skin all round the free edge of the valves; the changes which now occur agree with what are seen during the fixation of a cheilostomatous larva. The corona, pyriform body, nervous system, and a portion of the musculature then undergo degeneration, and form a mass of globules enveloped by the mesodermic layer. The thickened plate of the ectoderm soon afterwards proliferates rapidly, and forms an invagination below the cuticle, which does not itself take part in it.
Arthropoda.
Segmental Sense-Organs of Arthropods.t—Mr. W. Patten states that the cephalic lobes of Acilius are composed of three segments, each of which contains a segment of the brain, optic ganglion, and optic plate. It is very probable that these characters are common to all Insects. The segmental nature of the eyes is more clearly seen in the embryos of scorpions, spiders, and Limulus, where it can be shown that they are serially homologous with one or more pairs of sense-organs on each segment of the thorax. If the cephalic lobes of scorpions could be stretched out the eyes would lie, as in Acilius, on the thickened outer edge of each segment. This thickened edge is represented in the post-oral region of the pleure of the thoracic segments, each of which bears two large sense-organs close together near the outer edge of the
* Comptes Rendus, eviii. (1889} pp. 1023-5. t Journal of Morphology, ii. (1889) pp. €00-2.
502 SUMMARY OF CURRENT RESEARCHES RELATING TO
base of the legs. Mr. Patten thinks it is clear that the eyes are serially homologous with these thoracic sense-organs. The latter contain a cavity, shaped like the bowl and stalk of a goblet, lined with striated cuticle similar to that found at an early stage over the eyes of Acilius. The ventral cord and brain of Arthropods are at first composed entirely of minute sense-organs, which in scorpions have the same structure as the segmental ones at the base of the legs. Further details are promised.
a. Insecta.
Formation and Fate of Polar Globules in Eggs of Insects.*— Dr. H. Henking has examined the early stages of development in the eggs of various Insects.
In the egg of Pyrrhocoris apterus the first polar globule appears three or four hours after deposition; it lies ina shallow depression of the marginal zone of protoplasm ; below it may be seen the second globule in a more or less advanced stage. When the first embryonic cells begin to be formed within the egg, the globules come to be placed freely in a cavity which is altogether surrounded by the marginal protoplasm; they have not yet, however, acquired their definite position, In eggs about twenty hours old the globules lie outside the protoplasm on the surface of the ventral yolk-material. The author’s opportunities of observation have not as yet enabled him to definitely settle the fate of these bodies, ~ but he is satisfied that the globules are again taken up by the egg. In the case of various Lepidoptera, Diptera, and Hymenoptera, Dr. Henking has not been able to observe the expulsion of the polar globules. In Tenebrio molitor one is certainly expelled, and the same is the case in Lampyris splendidula.
Vision of Insects.t—Dr. F. Dahl, who believes that Insects can dis- tinguish form, traverses certain conclusions of Prof. Plateau, for which he does not believe there are physiological grounds. He relates an account of an experiment which he made with a bee (Hylzus morio), whose enemy is the spider Attus arcuatus ; thinking that the olfactory sense might give the insect warning, he killed a spider, and smeared a paper-sphere with its blood, but of this the bee was not at all afraid. The male of the dipterous Dolichopus plumipes has a beautiful and regular pinnation of the first tarsal joint of the middle leg; this apparatus cannot be of use during copulation. When the insects were pairing it was observed that the male hovered over the female in such a way as to bring its middle tarsi close to the eyes of the female.
Dr. D. Sharp ¢ devoted a large part of his Presidential Address to the Entomological Society of London to the subject of the vision of Insects. He thinks we may fairly conclude that it is quite uncertain what insects do see, or whether they see at all, if we use the word seeing in association with our own plane-picture seeing. He lays stress on the point that, certain central structures in connection with the verte- brate sense of sight not being present in insects, other structures to compensate for their absence may be expected to occur in more direct connection with the eye. If so, it becomes highly probable that the functions of the insect-eyes are not only dissimilar from ours, but are
* Nachr. K. Gesell. Gottingen, 1888 (1889) pp. 444-9. + Zool. Anzeig., xii. (1889) pp. 243-7. t Trans. Entomol. Soc. Lond., 1888 (1889) pp. xlviii—Lxix.
ZOOLOGY AND BOTANY, MIOROSCOPY, ETC. 503
also more complex. He thinks that, from the anatomical side, we as yet know very little about how or what an insect sees, and he thinks it highly probable that its sight is very different from our own, and that continuous picture-vision forms no part of it; he thinks it possible that the compound-eye may have two or three distinct kinds of perception. At the same time he is of opinion that the ocular powers of insects are very perfect in their way, although that way may be very different from ours.
Hermaphroditism in Gastropacha.*—Prof. P. Bertkau describes a case of external hermaphroditism in Gastropacha quercus, where the right antenne and wings were those of a female, those on the opposite side characteristically male. In other ways the external . secondary characters were mingled, but the thorax and posterior body were wholly female. The state of the internal organs was at the same time investi- gated, obviously a point of much importance. The gonads were wholly degenerate, but there were almost normal female ducts and auxiliary structures. There was no hint of internal male organs. Bertkau believes that an individual has rudiments of both kinds of secondary sexual characters, that predominance of one sex in the organism suppresses the secondary features of the other, while complete atrophy of the essential organs is naturally enough associated with an external average. The author notes the occurrence of 315 cases of “ hermaphro- ditism ” among Arthropods :—8 Crustaceans, 2 Arachnids, 305 Insects. Of the latter, 244 Lepidoptera, 48 Hymenoptera, 9 Coleoptera, 2 Orthoptera, and 2 Diptera are known. Among Arachnids, a specimen of Dizea dorsata was male as regards cephalothorax, limbs, and palps, but female in the hinder part of its body.
Myrmecophilous Insects.j — Herr E. Wasmann continues his interesting investigations on the life of myrmecophilous beetles and their relations to the ants. He distinguishes (1) true guests which are cared for and fed by the ants (Atemeles, Lomechusa, Claviger); (2) forms which are tolerated but are not treated with special friendliness, and which feed on dead ants or rotting vegetable material (Dinarda, Heterius, Formicoxenus, &c.); (8) ant-eating species, pursued as enemies, or only tolerated as a matter of necessity (Myrmedonia, Quedius brevis, &c.), to which may be added parasites like Phora. The three sets are not rigidly separable.
Atemeles and Lomechusa have taken on some of the habits of their hosts, aud are more adapted than other myrmecophilous insects. The best known species of Atemeles (A. paradoxus and A. marginatus) are found most frequently in the nests of Myrmica, more rarely in those of Formica and others. On the contrary, A. pubicollis seems to be more frequent in Formica nests. The species of Atemeles are lively animals, constantly moving their feelers, and experimenting with everything. If one be attacked by a hostile ant, it first seeks to pacify its antagonist by antennary caresses, but if this is unavailing it emits a strong odour which appears to narcotize the ant. Wasmann describes how the ants feed the Alemeles and are caressed and licked for their care, how one
* Verh. Nat. Ver. Preuss. Rheinld. (SB. Niederrhein. Gesell.), xlv. (1888) pp. 67-8.
+ Biol. Centralbl., ix. (1889) pp. 23-8; Deutsche Entom. Zeitschr., 1886, pp. 49-66, 1887, pp. 108-22; Tijdschr. vy. Entom., xxxi. (1888) p, 84.
504 SUMMARY OF CURRENT RESEARCHES RELATING TO
Atemeles feeds another, or even as a rarity one of the hosts. Yet the beetles feed independently on sweet things, dead insects, and even the unprotected young of the ants. The guests are licked and cleaned by the hosts, as well as vice verséd; but the beetles are in reality quite dependent upon the ants.
As to Lomechusa, it is represented in Central Europe by a single species, LD. strumosa, which is almost always found with Formica sanguinea, though occasionally with other forms. This beetle is much larger, plumper, and more helpless than Atemeles ; its odour is different and very like formic acid ; its relations to the hosts are more passive, yet it can feed independently, for instance, on the larve and pupz of the anits.
The other guests are rather pests than pets. They almost all live on animal food, are often protected simply by prestige or by their odour. The minute Oligota, Homalota talpa, Myrmecoxenus, Monotoma, Hysteride, the small guest-ant Formicoxenus in the nests of Formica rufa, &c., appear to escape unnoticed.
On a change of abode, the myrmecophilous insects follow their euests, or, as in the case of Lomechusa and Atemeles, they are taken with them by force. While the ants themselves are well known to be very exclusive, the guests can be shifted from nest to nest or even from species to species. As Wasmann says, the guests seem to have ‘international relations.”
In commenting upon the above facts, Prof. Emery regards it as | certain that the semi-domesticated, and in one sense parasitic forms like Atemeles and Lomechusa, ave descended from thievish forms. They retain some of the original traits, just as dogs and cats do in their recently acquired tamed state.
Butterflies’ Enemies.*—Mr. 8. B. J. Skertchly, who has had oppor- tunities of studying the question in virgin forest, discusses the habits of the enemies of Butterflies. He comes to the conclusions that mimicry is a protection from foes which attack butterflies on the wing ; protective resemblance is a protection from foes which hunt sleeping prey; mimicry was a protection from birds, but birds seldom attack butterflies now, though butterfly-catching birds were formerly more plentiful. The comparative rarity of mimicry shows the danger to have been of relatively short duration. The shyness of butterflies is a further proof of danger; it is now probably an inherited instinct. Protective resemblance is almost universal, and .is a protection during the sleeping hours. Ants seldom capture living butterflies. The symmetrical mutilations of butterflies point to lizards and perhaps small insectivorous mammals as the foes which hunt for sleeping butter- flies. It is concluded that the amount of danger feared is measurable by the efforts made to avoid it.
Alimentary Canal of Larval Lamellicorns.t—Sig. P. Mingazzini communicates some new facts in regard to the structure of the alimentary canal in the larve of some phytophagous Lamellicorns, belonging to the genera Oryctes, Anomala, Cetonia, and T'ropinota. He notes the presence of unstriped muscles in the mesenteron, for at least a period of the larval life, and describes a new type of connective tissue and cry stalloids in the
* Ann. and Mag. Nat. Hist., ili. (1889) pp. 477-85, + Boll. Soc. Nat. Napoli, ii. (1888) pp. 130-4.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 505
nuclei of some cells in the midgut of Oryctes. The median ventral groove of the midgut in the larve of Oryctes, Cetonia, and Tropinota is a sort of glandular cecum with a digestive secretion, The sac which forms the median portion of the proctodeum is the absorptive part of the intestine in these larve.
Bees and Flowers.*—Dr. M. Kronfeld corroborates the old observa- tion, which even Aristotle recorded, that bees do not fly at random from one flower to another, but for a longer or shorter period restrict their visits to one species. Three times before a bed of Cucumis the observer detained a bee, and watched it return when liberated to the same kind of flower though others were there in abundance. At a bed including eight different kinds of flowers the bees were apparently blind to all but one species. In a meadow with abundance of inviting flowers, repre- senting nearly a score of species, Herr Kronfeld saw a humble-bee visit within ten minutes twenty-eight heads of goat’s-beard, and no others. The observations, therefore, show a considerable degree of constancy in the bees’ visits.
Stigmata of Hymenoptera.j—M. G. Carlet finds that the stigmata of the Hymenoptera are always open, and that there is not the least trace, at their orifice, of any obturator apparatus. They are of extremely small size, and have, consequently, received but little attention; more- over they are generally covered externally by hairs which are often ramose, and which serve to prevent the introduction of foreign bodies, even in the form of fine dust. The tracheal trunks may be opened or closed at the will of the insect; this mode of closure, which the author calls opercular, is effected by means of a special tracheal muscle which is inserted in the trachea, above a cleft which is found on it in front of the stigma; the tracheal muscle raises the upper lip of this cleft, that is to say the operculum, in the mode of the lid of a snuff-box. The difficulty of the investigation to which M. Carlet has lately devoted himself may be estimated from the fact that this muscle is more delicate than the finest silk-thread of commerce.
Development in Egg of Musca vomitoria.t—Dr. A. Voeltzkow has published a full account of his researches on this subject. Tio our notice of his preliminary communication § we may now add the follow- ing. The Malpighian vessels are formed as evaginations of the hind-gut, and the sucking stomach as an evagination of the fore-gut. The salivary glands are formed by invagination of the ectoderm in the anterior part of the head and are laid down separately; later on they open by a common efferent duct into the mouth. The ventral cord, when fully developed, consists of two longitudinal cords of nerve-fibres which are inclosed by nerve-cells ; in correspondence with each segment the nerve- cells are separated by a ventral mass of cells. The longitudinal trunks lie close to one another, but do not fuse, being separated where they touch by a fine layer of cells. In the course of its further development the ventral cord shortens considerably ; the author does not agree with Weissmann that the indications of the earlier segments are lost. He is
* Biol. Centralbl., ix. (1889) pp. 28-30.
t+ Comptes Rendus, eviii. (1889) pp. 862-3.
} Arbeit. Zool.- Zoot. Inst. Wiirzburg, ix. (1889) pp. 1-48 (4 pls.). § See this Journal, 1888, p. 572.
506 SUMMARY OF CURRENT RESEARCHES RELATING TO
inclined to accept Hatschek’s statement that the brain arises from the lateral parts of ectoderm laid down separately.
A Spinning Dipteron.*—Prof. J. Mik describes a remarkable veil which the male of Hilara sartor Beck. carries about with him in his flight. This veil is a thick filamentous tissue, without any “sort of seam in its longitudinal axis,” or “S-shaped threads,” as Becken describes. It is not borne on the back of the abdomen of the male, but is held on the under surface of the body by the feet.
Biology of Gall-producing Species of Chermes. ,—Dr. F. Low has a contribution to the interesting subject of the biology of gall-producing species of Chermes which is now attracting so much attention. His experiments enable him to confirm two of the statements of Blochmann and Dreyfus—the wandering of the winged individuals of the first or gall-ceneration of Chermes abietis from the pine to another species of Conifer, and the division of this generation into two unequal parts, each of which forms the commencement of a special series of developmental changes. He also makes a contribution to the literary side of the question.
Dr. L. Dreyfus ¢ has again § a communication on the subject; he finds that Ch. hamadryas must cease to be regarded as an independent species, and the animals which have been so called must be considered to belong to the developmental series of Ch. strobilobius ; there are, therefore, no species which can now be said to be confined to the larch.
Egg of Melolontha vulgaris.||—Dr. A. Voeltzkow has made a study of the development of the egg of Melolontha vulgaris, but unfortu- nately he was not able to investigate the earliest stages. The germinal layers are formed in the manner first described by Kowalevsky for Insects, namely, by invagination in the middle line of the germ-stripe, the groove thus formed being converted into a tube; this tube is flattened out in a dorgo-ventral direction, becomes cut off from the blastoderm, and differentiated into an outer and an inner layer. ‘The cells of either layer fuse completely with one another, so that no sign is left of the previous tube or cleft. The author is not in agreement with Heider, for he is unable to accept the account of the differentiation of the lower layer into two distinct cell-layers. A very important point in Heider’s memoir is the account of the formation of the mid-gut; but Dr. Voeltzkow’s own investigations, coupled with a critical notice of the work of other observers, seem only to lead him to the conclusion that the question of its origin is well worthy of renewed investigation, which he proposes to take with Blatta as his subject.
Anatomy of Blattide.{—Dr. E. Hasse states that Mr. EH. A, Minchin’s lately discovered ** organs in Periplaneta orientalis are, as their discoverer supposed, stink-glands; it may be easily proved in the larve. The hairs which take up the secretion of the glands and diffuse it call to mind those described by Fritz Miller as associated with the stink-clubs of the females of Maracuja. In both the secretion appears to be of an oily character. Comparable also are the eversible dermal
* Verh. K. K. Zool.-Bot. Gesell., xxxviii. (1888) pp. 97-8.
+ Zool. Anzeig., xii. (1889) pp. 290-3.
t T. c., pp. 293-4. § See this Journal, ante, p. 380. | Arbeit. Zool.-Zoot. Inst. Wiirzburg, iv. (1889) pp. 49-64 (1 pl.).
q Zool. Anzeig., xii, (1889) pp. 169-72. ** See ante, p. 204.
ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 507
appendages found by Gersticker in Corydia, and the structures of similar function found in larve, and lately described by Klemensiewicz. Some account is given of the peculiar organs found between the sixth and seventh dorsal plates of Phyllodromia germanica.
8. Myriopoda. Spinnerets of Myriopoda.*—M. J. Chalande found in Scolopendrella
immaculata an apparatus composed of two distinct glands, which open outwards in the two appendages which are placed on the margin of the anus. ‘They have the form of elongated tubes which end blindly about the fifth anal segment. The anterior portion forms the gland proper and the hinder part its excretory canal. The gland is occupied by a single large cavity filled with the secreted substance ; its wall consists of fine cells charged with fine granulations. The terminal appendages, which are formed by a single lanceolate joint ending ina long and strong spine, are traversed by a cavity at the end of which is an aperture. The secreted liquid is remarkable for its great viscosity, and does not mix either with water or glycerin; on coming. into contact with air it hardens rapidly. The threads thus formed differ from those of Spiders in being not elastic but fragile, like a thread of glass.
Myriopoda of Mergui Archipelago.t—Mr. R. I. Pocock hag an account of the Myriopods collected by Dr. Anderson ; they are, appa- rently, the first recorded from these islands, and they are, in many cases, referable to species which have been described from the Oriental region. Those that are new are, with one exception, small and incon- spicuous individuals, which would in all probability have been overlooked or ignored by any but a scientific collector. Of the Chilopoda only one —a species of Himantarium—is new; of the Diplopoda, Glomeris has one, Paradesmus two, Spirostreptus two, and Spirobolus one new species. During the printing of his paper the author was enabled to examine two large collections of Burmese Myriopods, and he has now found that the Myriopod fauna of Mergui has certainly been derived from that of South Burmah. He has therefore described the new Glomeris from Mergui not as a new species, but as a variety of a new Glomeris—G. carnifea—from Tenasserim, arguing that the continental form ig the parent of that found in the island.
y. Prototracheata.
Maturation of Ovum in Cape and New Zealand Species of Peripatus. {—Miss L. Sheldon has had the opportunity of studying the maturation of the ovum in three species of Peripatus. In P. capensis and P. Balfouri the ova arise by a growth of some of the nuclei of the germinal epithelium ; apparently any of the nuclei may give rise to ova, Each ovum has a large round central nucleus, and is surrounded by a layer of protoplasm, which is not separated from that of the germinal epithelium. As the ova increase in size they become surrounded by a thin shell. As the nucleus passes to the periphery it is homogeneous, and has only slight traces of a reticulum. After the disappearance of the germinal spot the wall of the germinal vesicle becomes irregular in
* Comptes Rendus, eviii. (1889) pp. 106-8. + Journ. Linn. Soc. Loud., xxi. (1889) pp. 287-303 (not 330 as printed) (2 pls.). t Quart. Journ. Micr, Sci., xxx. (1889) pp. 1-29 (3 pls.).
508 SUMMARY OF CURRENT RESEARCHES RELATING TO
outline and then disappears, its contents becoming fused with, and in- distinguishable from, the cell-substance. As the ovary is full of spermatozoa the ova are probably fertilized in it. They thence make their way into the uterus. The youngest uterine ovum observed had no nucleus ; a small spindle appears at one point at the periphery of the egg, and a male pronucleus is present at the opposite side. The spindle divides twice to form polar bodies, and the remainder of the spindle remained as the female pronucieus ; it lies at a little distance from the surface, and is lobed. The male pronucleus is large and rounded; the two probably conjugate, though this has not been observed. The re- sulting nucleus passes to the periphery; it is large and lobed, and soon becomes surrounded by a large mass of dense protoplasm.
An account is also given of the maturation of the ovum in P. Nove- Zealandiz, which differs not inconsiderably from that of the Cape species; for example, spermatozoa are present in the receptacula seminis and not in the ovary; the nucleus is at one period vacuolate, and no polar bodies have as yet been observed.
In conclusion some general remarks are made on the origin of the ova from germinal epithelium, the disappearance of the germinal vesicle, the formation of the polar bodies, and the formation of the yolk. As to the last question; while it has been suggested that the yolk arises in the protoplasm of the egg itself, from the breaking up of the germinal vesicle, or from the follicle cells, it is of interest to observe that P. Nove-Zealandiz not only affords an example of all these three methods, but also a fourth, for the yolk arises from yolk which is present in the ovary itself. Miss Sheldon does not think she could have failed to see polar bodies in P. Nove-Zealandiz had they been formed, and she thinks that their absence in that species and their presence in the Cape species can only be explained by supposing that they are in some way dependent on the yolk, since in it lies the main difference between the eggs. If this be so, it is clear the polar bodies cannot have the significance which Weismann attributes to them, and in any case the similarity between the two polar bodies in the Cape species is not what we should have expected if their meaning were so different as Weismann suggests.
6. Arachnida.
Life-histories of Glyciphagus domesticus and G. spinipes.*—Mr. A. D. Michael finds that there is a hypopial stage in the life-history of Glyciphagi, just as there is in that of Tyroglyphus, but it is far less developed, and is not, so far as is known, an active stage. At present we do not know whether it occurs in all species, but we do know that it does not occur in the life of every individual of a species. The stage is not the result of desiccation and other unfavourable circumstances, but occurs as often under favourable conditions. In the species inves- tigated it occupies the period between the penultimate ecdysis and that immediately previous.
In G. spinipes the Hypopus is fully armed, and capable of moving its legs, but not of walking or other active movement; as a rule, it does not leave the skin of the young nymph within which it is formed; the more adult nymph is formed within the Hypopus while the latter is still within the young nymphal skin. In G. domesticus the hypopial stage is
* Journ. Linn. Soc. Lond., xx. (1889) pp. 285-98 (1 pl.).
ZOOLOGY AND BOTANY, MIOROSCOPY, ETO. 509
even more rudimentary, its representative retaining only the general form of the creature, and having no legs or other external organs.
Encystation of Glyciphagus.*—M. P. Mégnin describes the process of encystation in Glyciphagus cursor and spinipes. When extinction appears inevitable the following remarkable life-saving modification was observed. The organs liquefy, their substance forms a gelatinous spherical mass within the body, and this mass becomes enveloped in a cyst. This remains inert, but may be blown about like a seed with the body as a parachute. If it land in favourable environment, rapid seg- mentation and budding occur within the cyst, and a new Glyciphagus emerges. M. Mégnin reports a case where myriads of these Acarids appeared very inopportunely from their cysts in a preserved-meat manu- factory, which some years previously had been used for the production of bone buttons.
New Genus of Hydrachnids.t—Herr F. Koenike describes a new genus of Hessian Hydrachnida, which he calls Teutonia primaria ; it appears to be allied to Limnesia and Sperchon, and to connect these genera with one another.
Accidental Parasitism on Man of Tyroglyphus farine.t—M. R. Moniez deals with the occasional presence on Man of this common Acarid. It was observed at Lille during the handling of wheat imported from Russia and arriving in so dry a state that no kind of fermentation could go on, so that there was no food for the mites. It is probable that they were cast into the air, and so reached the skin, where their powerful organs enabled them to pierce the skin and suck the fluids beneath.
Marine Acarina of the Coasts of France.$—M. Trouessart thinks that the Acarina which are truly marine—the Halacaride—ought to form a distinct family and not a subfamily of the Trombidide, as, indeed, was proposed by Murray in 1875. The young appear to be carnivorous and the adults herbivorous in habit. Like many other Acarina, they are parasitic when young, and merely commensals when adult. They thrive well in brackish water, and resist for a long time the influence of fresh water. ‘They abound in the coralline zone. In the monograph which M. Trouessart has in preparation seventeen species will be described, while English naturalists have as yet only reported the presence of ten on our coasts; several of them are, of course, common to the two faune.
Marine Hydrachnida. ||--Dr. R. v. Schaub has some notes on the generic and specific characters found in Pontarachna, and some observa- tions on the well-known genus Midea He comes to the conclusion that Asperia Lemani (Haller) is the female and Nesxa Kenikei (Haller) the male of M. elliptica (Kcenike).
Morphology and Larve of Pantopoda. {—Herr G. Adlerz commu- nicates some observations on the morphology and development of the Pantopoda. The first part of his paper deals with the homologies cf
* Journ. Anat. et Physiol. (Robin), xxv. (1889) pp. 106-10 (1 fig.),
+ Zool. Anzeig., xii. (1889) pp. 103-4.
t~ Comptes Rendus, eviii. (1889) pp. 1026-7. § T.¢., pp. 1178-81.
|| SB. K. Akad. Wiss. Wien, xeviii. (1889) pp. 163-79 (2 pls.).
{| Bihang K. Svenska Vet. Akad. Handlingar, xiii. No. iv. (1888) 25 pp. (2 pls.). 1889. 2N
510 SUMMARY OF CURRENT RESEARCHES RELATING TO
the appendages, with special reference to those of Nymphon strémii and Phoxichilidium femoratum. In a second chapter the author discusses the larval stages of the last-named species.
e. Crustacea.
Development of Amphipoda.*—Madlle. M. Rossiiskaya has studied the development of Orchestia littorea. The egg, which is deep-violet in colour, and oval in form, is covered by a single membrane, the chorion. The first two blastomeres differ slightly in size, and the later segments are still more unequal. Segmentation stops when thirty-two blastemeres have been formed; protoplasm is then detached from the yolk in the form of amceboid cells, which become scattered over the whole surface of the egg. The blastoderm is formed by the approximation of from four to ten cells, which contract their pseudopodia, become polyhedral, and form a small, irregular, white spot. Around this, cells elongate and become divided in the direction of the radii of a circle, whose centre is the blastodermic spot. Although the cells on the dorsal surface multiply, their number does not increase; this shows that they migrate to the ventral surface, where they aid in enlarging the blastodermie spot.
After the blastoderm has completely covered the ventral surface it elongates at one pole much more rapidly than at the other; the former of these poles is the oral, and the other the aboral. At last the whole surface of the egg is covered by the blastoderm.
During the formation of the endoderm, very interesting sections were obtained; these showed that each blastodermic cell of the ventral surface consists of two parts; the external portion has a condensed pro- toplasm which stains well, while the internal part stains feebly, and seems to contain yolk; in several of these cells there are two nuclei. These sections show exactly the mode in which nutrient matter is taken in. When the blastoderm covers about two-thirds of the surface of the egg, a dorsal organ is formed on one of its sides; this has the appearance of a funnel, and is made up of large pyriform cells with large nuclei. When the blastoderm completely envelopes the nutrient yolk, it secretes the larval tissue, which is very delicate, transparent, and structureless.
As in Oniscus murarius, the endodermic cells arise from a small part of the blastoderm. When the dorsal organ has taken up its definite position on the median line of the dorsal surface, the endodermice cells, which, till now, have been multiplying in the interior of the yolk, migrate towards its surface, and form two lateral bands, which are applied against the abdomen; these bands are the walls of the mid- intestine. Shortly after the intestinal tube is completely closed, the cells which form it change in appearance ; instead of being flattened and solid they become large, prismatic, and so charged with vacuoles that the protoplasm only forms a delicate layer on their walls. There then appear three grooves, two of which are dorsal and one ventral; the former cut off, so to say, the true intestine from the intestinal sac, the latter divides the rest of the intestinal tube into two hepatic sacs.
The gonads are formed thus; in the dorsal wall of the intestine, at the two lateral points at which they touch the hepatic sacs, the epithelial cells become cylindrical in form, and multiply rapidly ; the cells of the hepatic sacs, where they touch the intestine, simultaneously undergo the same changes. ‘Thus there are formed two solid masses of cells, placed
* Bull. Soc. Imp. Nat., 1888 (1889) pp. 561-81 (2 pls.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. Hil
on either side of the intestine. These become hollow, and separate from the walls which produced them.
The mesoderm is first formed from the inner cells of paired ecto- dermic swellings. The nervous system commences with the formation of cephalic ganglia on either side of the head; the ganglia of the ventral chain appear as paired ectodermic thickenings.
Madlle. (Dr.) 8. Pereyaslawzewa* describes the development of Caprella ferow. The ova have a transparent but very compact chorion, which does not allow of the passage of much colouring matter or pre- servative fluid. The nucleus, which is placed at the centre of the egg, is surrounded by a thick layer of protoplasm (formative yolk), covered by a layer of nutrient material, which contains a number of fat-drops. After the seventh stage, the segmentation loses its regularity, and becomes more and more difficult to study ; as the formation of the blasto- derm is being completed, it thickens on the ventral surface along the median line, while remaining more delicate elsewhere. When its for- mation is completed, and it covers the dorsal surface of the embryo, the boundaries of the cells are no longer recognizable, and the blastodermic layer has the form of a mass of transparent, perfectly clear, bodies, which envelope and close the yolk, As the dorsal organ is being formed, a transverse groove appears on the ventral surface, which carries down the blastoderm into the midst of the vitelline masses ; this is the commencement of the abdomen. Simultaneously two lateral prominences appear above the dorsal organ; these represent the two halves of the head, which, therefore, are at first separate from one another. The development of the body occupies fifteen days.
In the course of the growth of the blastoderm, the constituent cells divide in two directions, radial and tangential; the thickest cells of the ectoderm are found in the thickenings which go to form the extremities, and in the ganglia of the ventral chain. The stomodeum is developed shortly before the rectum; both are developed in exactly the same way as in Gammarus. ‘lhe formation of the mesoderm coincides with that of the extremities ; at first its elements accumulate in the ectodermal swellings which have given rise to them. In the phases which corre- spond to this period of development, the mesoderm nowhere forms an intermediary layer between the ecto- and endoderm. Later on, the division of the mesodermic cells becomes very active, they pass the boundaries of the cavities of the swellings, and become collected in places where muscles will be formed. Before, however, these appear, the heart begins to be developed, and as it is developed the dorsal organ disappears.
In describing the development of the endoderm and its derivates, it is pointed out that the hepatic appendages are developed from endo- dermal cells which form two independent tubes.
British Amphipoda.} —In the first of his notes on British Amphipoda the Rev. Dr. A. M. Norman describes a new genus and some Cidiceride. The former, which is called Megaluropus, is remarkable for the large round eye which is situated on a greatly projected head-lobe, and the expanded foliaceous branches of the last uropods. It appears to be nearly allied to Elasmopus. The new species, M. agilis, has been taken
* Bull. Soc. Imp. Nat., 1888 (1889) pp. 582-97 (2 pls.), + Ann. and Mag. Nat. Hist., iii. (1889) pp. 445-60 (3 pls.
ny 2 NF
512 SUMMARY OF CURRENT RESEAROHES RELATING TO
in the Firth of Clyde, Liverpool Bay, Devonshire coast, Jersey, and Firth of Forth ; it is most frequently taken by means of the surface-net at night, and is a very active swimmer. ;
The Cidiceride noticed belong to the genera Monoculodes, Hali- medon, and Aceros; Aceros phyllonyx was taken sixty mules north of Peterhead, in 69 fathoms; it may be distinguished from all other British Cidiceride by the total absence of a rostrum, and also from Halimedon, which it most closely approaches in the form of the gnatho- pods, by the structure of the antennules, which, in the female, have a remarkably long peduncle.
Amphipod Family of Scinide.*—Prof. C. Chun finds that the Amphipoda of Stebbing’s family Scinide (Tyronide of Bovallius, and Fortunate of Chun) are pelagic animals which only exceptionally come to the surface in warmer zones ; their reduced eyes show that they are adapted to live in imperfectly illuminated regions. But little has been till lately known about their organization, and their place in systematic classifications is open to revision. Prof. Chun would form six sub- orders of the Amphipoda :—1, Caprellidea ; 2, Crevettina ; 3, Synopidea ; 4, Amphipoda Gammaroidea, with the families Lanceolide and Vibilide ; 5, Tyronide, with the family Scinide; and 6, Hyperine, with the three tribes Hyperide, Phronimide, and Platyscelide. In the Tyronide the body is not compressed, the head small, the eyes small or rudimentary; the upper antenne have no secondary flagellum ; basal joint of flagellum very large, sword- or lancet-shaped. Lower antenn: rudimentary in females, mandibles and maxillipeds without palps, &e.
Ostracoda of North Atlantic and North-western Europe.{— Prof. G. S. Brady and Canon A. M. Norman have issued a monograph of the marine and fresh-water Ostracoda of these districts; the present memoir treats only of the Podocopa, and is intended to supplement Prof. Brady’s well-known monograph of the recent British Ostracoda.}
Parasitic Crustacea.§S—MM. A. Giard and J. Bonnier have a note on an Epicarid parasitic on an Amphipod, and on a Copepod parasitic on an Epicarid. The Epicarid was found parasitic on Ampelisca diadema, whence two specimens were taken. They belong to the group of Cryptoniscina, and were both females with young. ‘The whole body is converted into a vast incubatory chamber, closed by two lateral plates which extend from the first to the fifth thoracic segment; they are united along the middle line so as to leave only an aperture at either end for the passage of water. On the dorsal side are five metameric bands, corresponding to the first five thoracic somites; on either side of the body, on each of the wings, there are conical eminences, which are probably the vestiges of limbs. On the head the maxillipeds are alone well developed.
The terminal part of the body is curved towards the rest in such a way as to complete the incubatory chamber by a posterior cavity, which is likewise filled with eggs. This curious parasite is called Podascon della Vallei, a new genus being requisite for its reception.
* Zool. Anzeig., xii. (1889) pp. 286-90, 308-12.
+ Sci. Trans. R. Dublin Soc., iv. (1889) pp. 63-270 (16 pls.). + See Trans. Linn. Soc. Lond., 1868.
§ Comptes Rendus, eviii. (1889) pp. 902-5.
ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 513
On a specimen of Aspidophryxus peltatus the authors have found the females and two males of a very singular Copepod, which they call Aspidecia Normani. The female has the form of a miniature Sacculina ; it is fixed to the Mysis on which the Aspidophryxus is parasitic by a short peduncle, which ends in a sucker, and to the parasite by an elongated cord; on this cord the male was found. Towards the free end of the body were two ovigerous sacs, containing eight to ten segmenting eggs. ‘T'he males have a form somewhat similar to that of the males of Sphexronella Leuckarti ; they are fixed by a spiral chitinous filament secreted by cement-glands, and a large sucker allows the parasite to apply its oral apparatus to its host. At the hinder end of the body are two lateral lobes which contain the spermatophoral sacs. This new genus appears to be closely allied to the Choniostoma mirabile lately discovered by Hansen, and, with Spheronella, should be placed in the aberrant family of the Choniostomatide.
Morphology and Systematic Position of the Dajide.*— MM. A. Giard and J. Bonnier offer additional evidence in support of their view that the Dajide are intermediate between the Cryptoniscina and the Bopyrina. Dajus mysidis has five pairs of appendages, and the fifth pair, which escaped the notice of Gerstaecker, are the best developed and form the greater part of the incubatory cavity. The morphology of the head and thorax differs little from that of the similar parts in the Phryxina. The adult male presents the pleon which is characteristic of Phryxus, but the antenne and rostrum forcibly recall the structure of embryonic Cryptoniscina.
The study of Dajus simplifies that of Aspidophryxus ; the species lent to the authors by Dr. Norman had been determined as A. peltatus by G. O. Sars; but it appears to be distinct from that species and may be called A. Sarsi; the ditferences between the two species are minutely pointed out. Certain errors in Sars’s original description are so noted, and the correction of them shows that Aspidophryxus is more closely allied to Dajus than could previously have been imagined.
Tegumentary Coverings of Anatifer and Pollicipes.;—M. R. Koehler points out that the characteristic tegumentary coverings of Pollicipes have a very complicated structure, and do not at all merit the name of scales. The chitinous layer of the peduncle has on its surface a series of conical depressions, clothed by a membrane which is continuous with the general cuticle which covers the chitinous layer. This membrane does not, however, stop at the edge of the pit; it is prolonged freely, and forms a kind of cupola, the internal region of which is placed in the layer of chitin and exhibits very elegant longitudinal and transverse striz, while the outer half has a uniform dark-brown coloration. The internal region contains a rounded concretion which effervesces with acids. The external region is occupied by a whitish mass which com- pletely fills the cavity of the cupola; it is limited internally by a very fine membrane, which fuses with the cuticular layer. It is the whitish mass which gives the white colour to these so-called scales, while their edges are nothing else than the external borders of the cupola. At the base of each cupola there is a rounded orifice which is bounded by a slightly swollen edge; the edges are continuous with a tube, the wall of
* Comptes Rendus, cviii. (1889) pp. 1020-2. t T.c., pp. 755-7,
514 SUMMARY OF CURRENT RESEARCHES RELATING TO
which is always formed by the same cuticle as that of the wall of the cupola. These tubes traverse the chitinous layer, becoming more delicate as they approach its internal surface, but their lumen always remains perfectly distinct; they take a slightly sinuous course. It is by these tubes that the cupole receive the nutrient materials which they require.
The chitinous layer of the peduncle of Anatifer has no special covering, but the cuticle-membrane has certain thickenings which, to some extent, recall the arrangements which are observed in Pollicipes. These are hemispherical swellings with globules differentiated in their interior ; these latter are formed by the cuticle, and are received into pits of the chitinous layer. The formations are more complicated m Pollicipes, but in both genera they are continuous with similar fibres which traverse the subjacent chitinous layer in radiate fashion. The structure of the calcareous valves of the capitulum also presents some peculiarities in Pollicipes, for the valves are of considerable thickness, and the calcareous plates are divided into three or four strata by secondary layers of the cuticle. The general tissue of the plates is not compact as in other genera, but contains numerous lacune, which are absolutely empty.
Vermes. a. Annelida.
Influence of Nervous System of Annelids on Symmetry of the Body.*—M. L. Roule, who has studied the development of various Annelids, and especially of the Enchytrxidx, attempts a sketch of the development of the nervous system. The nervous centres are of epiblastic origin, and the first is the cephalic or frontal plate; it alone exists in those embryos in which the development is condensed, but it is not so with larve. These latter also have a subepiblastic nervous plexus which is chiefly placed under the vibratile oral corona; it some- times, as in Lopadorhynchus, becomes a compact ring. We have here a radially symmetrically nervous system, and the embryos are oval or spherical. The annular plexus is peculiar to the larva, aud disappears after the larval stage. The body next elongates and a third nervous rudiment arises in the metasoma; this is the future ventral nerve-cord.
At their first appearance the plates are merely local proliferations of the ectoblast, which are thicker in the centre than at the sides. Changes occur when the mesoblast begins to be developed, for this elongates with . the growth of the body, and the primitive radial symmetry is converted into the bilateral, which is preserved in the adult; the rudiments of the nervous centres are modified to follow this change of symmetry. Two chief centres of proliferation appear in each of the cephalic and medullary plates, and are arranged symmetrically around the new longitudinal axis which divides the body into two halves.
In the primitive types the medullary cords inclose, for the whole of their extent, an equal number of nerve-cells and fibrils, while in the higher types there is a differentiation into ganglia formed of cells only and of connective fibrils. The author cannot regard the phenomenon of the production of the metasoma by the prosoma as similar to an alterna- tion of generation, as does Kleinenberg. Nor, as ke will show in a
* Comptes Rendus, eviii. (1889) pp. 359-61.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. ais
more extended memoir, can he accept the views of the just-mentioned naturalist or those of Sedgwick as to the relations between Meduse and Annelids.
Epidermis of Serpulide.‘—WM. A. Soulier has had some difficulty in examining the structure of the epidermis in these worms. The cells are not sharply distinguished, and they vary in the degree to which they stain, while it often happens that they become retracted. Like Claparéde he is able to distinguish a true epidermis from a hypodermis; in the former are numerous alveoli, some of which are found empty, while others are filled with granulations or a homogeneous liquid which stains intensely. These alveoli elaborate the mucus; they are surrounded by fibro-cells which stain less intensely. The hypodermis has a similar constitution; in certain cases it increases in thickness and forms swellings. Myzicola secretes a very thick tube in a few minutes, owing to the large number of these swellings which it possesses. The author is of opinion that the supporting and the muciferous fibro-cells of the epidermis of the Serpulide have their origin in the hypodermis, and that they are merely differentiated connective cells.
Marine Oligocheta of Plymouth.t— Mr. F. E. Beddard states that there are three species of Oligocheta common in the Sound at Plymouth, which are apparently identical with certain forms described by Claparéde from the shores of Scotland and France. One belongs to the genus Pachydrilus, and the two others are Clitellio arenarius and C. ater. Tubifex lineatus has been stated to occur at Plymouth, but this is a most mysterious species, Hoffmeister’s original description not rendering its identification possible.
Australian Earthworms.{—In his fifth communication on this sub- ject Mr. J. J. Fletcher describes twenty new species of earthworms, chiefly from New South Wales, but there are a few from Queensland and South Australia. They belong to the genera Megascolides, Perissogaster, Digaster, Pericheta, and Cryptodrilus; of the last there are eleven species. At present it would be premature to separate any as types of new genera, though it is obvious that that will have to be done, so remarkable are the characters of some of the species. Some fifty species of Australian earthworms are now known, but three or four times as many probably remain to be discovered. It cannot yet be certainly said that the interesting morphological points detailed by Prof. Baldwin Spencer in his recent memoir on Megascolides australis will be found to be of equal systematic value.
Green Cells in Integument of Aeolosoma tenebrarum.$S—Mr. F. E. Beddard describes the green-coloured spots of this worm as large cells with a thin peripheral layer of protoplasm containing a nucleus ; in the centre is a large giobule of oily appearance impregnated with the colour- ing matter; treatment with various reagents seems to show that this green pigment is not chlorophyll. The author suggests that it belongs to the class of respiratory pigments, with a number of which he com- pares it, and it seems also to be of value as a means of protection.”
* Comptes Rendus, eviii. (1889) pp. 460-3.
¢ Journ. Marine Biol. Assoc., i. (1889) pp. 69-71. ¢ Proc. Linn. Soc. N.S.W., iii. (1889) pp. 1521-58. § Proe. Zool. Soc., 1889, pp. 51-6 (1 pl.).
‘
516 SUMMARY OF OURRENT RESEARCHES RELATING TO
Anatomy of Hirudinea.*—Mr. C. O. Whitman has a preliminary notice of some new facts about the Hirudinea. As a group, they are characterized by the possession of segmental organs on the first ring of every somite. The diffuse or non-metameric arrangement which is seen in Nephelis and some other forms seems to have been acquired secondarily. ‘The author has shown that in all ten-eyed leeches the eyes represent enlarged, more or less modified, segmental sense-organs ; if this be true of other leeches, it would appear that the metameric sense-organs are earlier in origin than the non-metameric. In two. species of Clepsine it has been seen that the segmental sense-organs appear very early in the embryo, before the time of hatching, while the scattered organs arise later. ‘The labial sense-organs are serially homo- logous with ventral sense-organs, as the author will soon show. Mr. Whitman’s experience leads him to think that “ most of our reputed blind leeches will yet be made to bear testimony to the blindness of their observers.” Inanew Japanese marine leech, Branchelliopsis, eyes appear to be altogether wanting, but very careful search revealed the presence of at least two pairs of eyes. They have so little pigment that they cannot be seen from the surface, but the visual cells are there. Another new genus, Piscicolaria, from the smaller lakes of Wisconsin, comes nearer to being blind than any leech yet examined; the only evidence of an eye is a single large visual cell on either side of the head without a trace of pigment-investment. The test of a leech eye is the presence of visual cells; these are the large clear cells of Leydig; they always make up the bulk of the eye, and in the Hirudo pattern they are the only cells which are supplied by the optic nerve; their main axis is generally, though not invariably, parallel with the axis of the eye; in Clepsine and Branchelliopsis the nucleus lies on the side exposed to the light, the clear rod-like part of the cell being directed towards the pigment; the cells are practically inverted, the nerve-fibres entering at the nucleated pole. The chief distinction between the different patterns of eye and the typical sense-organ lies in the relative abundance of the clear cells.
The segmental sense-organs are double, both in structure and fune- tion; there is an axial cluster of elongated cells, terminating at the surface in minute hairs, and probably representing a tactile organ. Around and beneath the tactile cells are the large clear visual cells, so characteristic of the eye. We have, therefore, a visual and a tactile organ combined, both derived from a common mass of indifferent epidermal cells, and both supplied by fibres from a common nerve- branch. Incredible as the double nature of these organs may at first appear, there is no escape when we once understand the structure of the eye in Clepsine. Both the eyes and the segmental sense-organs develope as local thickenings of the epidermis, and at first the cells are alike in form, size, and structure; about the time the pigment begins to appear the two sorts of sense-cells begin to show a difference in size, and an indistinct boundary line appears between them.
It is urged that the metameric arrangement of the sense-organs of the Hirudinea is a matter of more importance than the latest writer on the subject—Apathy—appears to imagine. The key to the analytical study of the external form is to be found in the metameric disposition
* Journal of Morphology, ii. (1889) pp. 586-99.
ZOOLOGY AND BOTANY, MICROSOOPY, ETO. 517
of the sense-organs. The terminal somites are of the highest importance for specific diagnosis, and the annular composition, which offers so much of theoretical interest, cannot be deciphered without the use of these organs.
But the importance of the segmental character of the sense-organs is not to be measured by its usefulness in systematic determinations ; nowhere is a chapter in the evolution of sense-organs so perfectly pre- served as among the Hirudinea. These segmental organs appear to be identical with the lateral-line organs of Vertebrates, and it is suggested that they have formed the starting point for the organs of special sense in the higher animals, not excepting even the eyes of Vertebrates. Mr. Whitman thinks that if we take what are now incontestable facts in the phylogeny of annelid and arthropod sense-organs, and add to them the evidence in favour of the common derivation of the vertebrate organs of special sense, we shall not much longer be able to concede to the visual organs of Vertebrates the position of isolation they have so long held. In the study of this question we must remember that (1) verte- brate sense-organs must be assumed to be derived from invertebrate sense-organs, and the history of the latter must furnish clues to the genesis of the former; (2) in the development of special senses visual cells have made the widest departure from the primitive tactile cells; (3) the medullary plate of the vertebrate is undoubtedly an enormous extension of the ancestral invertebrate plate ; (4) sense-organs lying originally outside the neural plate have probably, in consequence of this extension of width, been brought within the medullary area; (5) the ancestral segmental sense-organs were not limited to a single pair of lateral lines, but there were several paired lines arranged symmetrically on the dorso-lateral and ventro-lateral surfaces.
A careful analysis of the annular composition of the body of Clepsine has enabled the author to find just twenty-six somites in front of the caudal sucker. Adding seven for the sucker, we have thirty-three, so that the number of somites determined by the external rings agrees precisely with the number of ganglia in the ventral chain.
The nervous system of Branchelliopsis is exceptionally interesting from the possession of veritable spinal ganglia; they are lodged in the anterior (sensory) of the two spinal nerves of each somite at a short distance from the ventral cord. A pair of colossal nerve-cells are found between every two consecutive ganglia in the ventral cord of this leech. They contain axial cells which undoubtedly correspond to the neuro- chord cells of other Annelids and probably to the colossal nerve-fibres of Amphioxus, Miiller’s fibres in Petromyzon, and Manthner’s fibres in Teleosteans.
In Clepsine chelydrz the spinal nerves issue as three distinct roots, the anterior of which unites with the middle to form one nerve, The agreement in form and structure between Piscicolaria and the Japanese Branchelliopsis is remarkable, for it is much closer than that between the fresh-water Piscicola of Europe and marine leeches.
All the Hirudinea may be derived from a form in which the somite consists of three rings; the author promises to explain in an early paper how these rings may become 4, 5, 6, or 12. Copulation in Clepsine is never direct, that is, by union of sexual pores; as in Nephelis and Peripatus, the spermatozoa are transmitted in spermatophores which are planted on any part of the exterior, preferably on the back. The
518 SUMMARY OF CURRENT RESEARCHES RELATING TO
gradual contraction of the sperm-case forces the contents through the skin in a steady stream, which can be seen under a magnifying power of twenty diameters.
Reproductive Organ of Phascolosoma Gouldii*—Mr. HE. A. Andrews has examined the reproductive organs of this Gephyrean. There is a single reproductive organ, made up of a solid mass of germ- cells supported by a structureless lamella projecting horizontally from between the retractor muscle-fibres and the enveloping peritoneal mem- brane; it is invested by a delicate nucleated membrane. Branches of the supporting lamella extend into the chief lobes of the organ, and are accompanied by elongated nuclei, similar to those of the peritoneal membrane. The germ nuclei have quite different staining properties from these nuclei; they increase in size towards the distal or free ends of the lobes of the organ, where they are surrounded by protoplasm ; this acquires definite cell-walls before the cells thus formed break loose from the others into the celom. In this last various stages in the growth of the ova, from the naked cells, 24 » in diameter, to the apparently mature, 185 » in diameter, were observed. An ovum in which the yolk measures 151 p had a vitelline membrane 3 yp thick perforated by innumerable pores, through which delicate pseudopodia- like processes pass out into an outer gelatinous case 12 yp, thick.
The reproductive organ of P. Gouldii is probably to be regarded as a thickened fold of the peritoneum supported by a structureless basement membrane or lamella; the nuclei of the peritoneum multiply rapidly to form a mass of germ nuclei, which, on the surface of the mass, acquire considerable cell-protoplasm; they are then forced out from the ends of finger-like processes into the ccelom by the growth of more deeply lying cells; the investing membranous part of the original peritoneum is ruptured at its ends, when this occurs.
B. Nemathelminthes.
Coffee-Nematode of Brazil.t—Dr. E. A. Goldi has a note on Meloi- dogyne exigua, the nematode which has for nearly twenty years been the cause of disease in the coffee-plantations of Brazil. The females are found to form cysts in swellings on the plants, and their vegetative organs are reduced, while their ovary is so swollen as to make the recognition of the vermian nature of the formless sack a matter of diffi- culty. The ova, which are 0°085 mm. long, have a transparent, thick and resisting membrane. The young are transparent, colourless, and cylindrical, the aboral end being drawn out to a long, fine point; at the terminal end of the esophagus there is a spherical, muscular swelling. The adults are more club-shaped in form, the aboral end being thicker than the oral, and ending ina sharp spine. A great deal remains to be discovered with regard to the discrimination of the sexes, the manner in which encystation is effected, and the wanderings of the young.
Physaloptera.{—Prof. M. Stossich gives an account of the general characters, the constituent species, and the distribution of the Nematode genus Plhysaloptera Rudolphi. Twenty-eight certain species already recorded are diagnosed, and notice is taken of nine others insufficiently
* Zool. Anzeig., xii. (1889) pp. 140-2. + Zool. Jahrb., iv. (1889) pp. 262-7. { Bull. Soe. Adriat. Sci. Nat., xi. (1889) pp. 36-59 (3 pls.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 519
known. The hosts comprise over a hundred reptiles, birds, and mammals, .
Female Genital Ducts of Acanthocephala.*—Herr P. Kniipffer corroborates the observations of Saefftigen on this subject. Indepen- dently of the latter, he demonstrated that the oviduct, described by Leuckart as single, is really double. The muscular structure or “ Glocke ” which receives the embryos from the body-cavity, the double ducts which are continuous with the former, the so-called “uterus” in which the ducts merge, the muscular and glandular terminal portion or “vagina,” are described and figured. Kniipffer’s researches included Echinorhyncus heruca Rud., E. polymorphus Bremser, E. globulosus Rud., E. strumosus Rud., E. pseudosegmentatus n. sp., which are all separately discussed. The author contributes some notes on the body-wall and the musculature, and denies the legitimacy of the genus Paradowites, which Lindemann sought to establish as distinct.
y. Platyhelminthes.
Gunda ulve.j—Herr A. Wendt is of opinion that the Planaria ulve of Oersted should be placed in the genus Gunda; the chief cause for this change lies in the close resemblance exhibited by the terminal organs of its generative apparatus to that of G. segmentata; the course taken by the oviducts, their union, and the opening of the unpaired oviduct into the uterine duct. In most fresh-water Planarians the uterus lies between the pharyngeal pouch and the penis, but in Gunda the penis is near the pharynx and the uterus is placed further back. Close similarity is also to be detected in the arrangement of the central nervous system.
On the other hand, the gonads do not in G. ulve exhibit the same marked segmental arrangement as in G. segmentata; before, however, judgment is passed on this point a larger number of marine Planarians must be examined.
Nervous System of Nemertines.t—Herr O. Biirger has a pre- liminary communication on the nervous system of Nemertines. On the whole he confirms the observations of Hubrecht. He has succeeded in discovering an anal commissure of the lateral nerves in Cerebratulus. The cesophageal nerve-trunks (vagus of Hubrecht) of that worm, of Langia, and of Polia are connected by a strong commissure, which con- tains ganglionic cells. The proboscis of Schizo- and Paleo-nemertinea is innervated by two ascending nerves given off from the ventral ganglion, which form a layer around a muscular zone. In the Hoplo- nemertinea ten to seventeen cords enter the proboscis, where their course is constant; they are connected by transverse fibrous bands, which sepa- rate the longitudinal musculature into two concentric layers. In the body there is an inner layer between the circular and internal longi- tudinal musculature, in addition to the peripheral nervous layer. Besides the already known sensory organs, the author found an altogether ter- minal epithelial invagination on the head, to which a nerve passes. The lateral cephalic pits of the Hoplonemertinea are provided with sensory cells which carry rods.
* Mém. Acad. Imp. Sci. St. Pétersb., xxxvi. (1888) pp. 18 (2 pls.). + Arch. f. Naturgesch., liv. (1889) pp. 252-74 (2 pls.). } Nachr. K. Gesell. Wiss. Gottingen, 1888, pp. 479-82.
520 SUMMARY OF CURRENT RESEARCHES RELATING TO
The histological characters of the central nervous system have been specially investigated ; it contains ganglionic cells and fibrillar substance, and a highly differentiated connective tissue. All the ganglionic cells are unipolar and devoid of membrane, and lie in sheaths of connective tissue. They are (1) cells with poorly developed body, darkly coloured, highly refractive nuclei, small and irregular in form; or (2) small, elongated, club-shaped cells, with oval nuclei and one or more nucleoli ; or (3) they are large, lightly coloured, flask-shaped, with large round nucleus and one nucleolus; or (4) they are colossal cells, which quickly take up colouring matters, and have a round nucleus with a projecting, large nucleolus.
The connective tissue is of two types; one is like the neurilemma, while the other consists of fibres which are given off from numerous, dendritically-branched processes of membraneless cells; they surround in large numbers the ganglionic cells, and may be easily recognized by their large oval nucleus and their peripheral zone of granules.
Helminthological Notes.*—Dr. von Linstow has another of his papers on new and imperfectly known worms. He has made an ex- amination of the internal structure of Pseudalius minor, taken from various organs in the common Porpoise. Physaloptera preputialis sp. n. was found in Brazil in Felis catus; it is chiefly remarkable for, the preputium-like duplication of the skin at the caudal end of the body in both sexes. Tr. campanula sp. n. is from the domestic cat of Brazil ; it is possible that this is the same as the form which Diesing named Tr. felis, but did not describe.
Echinorhyncus Dipsadis sp. nu. was found represented by fifteen examples in the enteric wall of a large Dipsas Blaudingi from the Cameroons, where it lived in its larval condition; encapsuled Hchino- rhyncus-larvee have been found in a number of snakes; their adult forms are probably to be sought for in birds of prey.
Cercaria terricola sp. u. was found in the liver of Helix ? vermiculata from Algiers, and C. terrestris sp. n. from the same organ in H. lens from Greece. The author concludes with some remarks on the anatomy of Bothriocephalus rugosus ; this species may be as much as 380 mm. long. The muscles of the parenchyma are well developed, but those of the subcuticular layer are very feeble. Of the former the longitudinal muscles are the best developed. The nervous system consists of two ganglia connected by a strong transverse commissure, and of two strong longitudinal nerves invested in a sheath. Outside the nerve-trunks there are ten vascular trunks, which are 0-016 mm. broad. On the whole, this species of Bothriocephalus is very different from B. latus, and recalls rather the Teenie of Birds.
Herr G. Brandes} gives an account of a very small Distomum (D. claviforme sp. nu.) which he found in large numbers in the rectum of Tringa alpina. Its body is divided into a longer flat anterior portion and a shorter spherical hinder part; the latter contains the generative apparatus. Another new species was found in the small intestine of the frog; it is 2°5 mm. long, and it is to be called D. turgidum. The author concludes with some notes on D. heteroporum from Vespertilio pipistrellus, which seems to have been somewhat misunderstood by Van Beneden.
* Arch. f. Naturgesch., liv. (1889) pp. 235-46 (1 pl.). + T.c., pp. 247-51 (1 pl.).
ZOOLOGY AND BOTANY, MICROSCOPY, ETO. AO
Prof. M. Stossich * continues his helminthological researches, de- scribing seven new species of Distomum, of which six are figured. Several other species of Distomum are discussed, and the occurrence of some other parasites (Tenia botrioplitis, Ascaris ensicaudata, &c.) is recorded.
The Species of Distomum in Amphibians.t—Prof. M. Stossich describes 16 species of Distomum parasitic in Amphibians, and seven others somewhat doubtful. <A list of 24 Amphibian hosts with their known Distomum parasites is furnished ; in Rana temporaria nine species occur, in R. esculenta ten.
Anatomy of Phylline Hendorfiij—Dr. von Linstow gives an account of the anatomy of this new species of ectoparasitic Trematode, which was found on the scales of Coryphena hippurus. The body is ovate in form, 8°7 mm. long, and 5*2 mm. broad; at the anterior end there are two suckers, and at the hinder end one which is very large. The former are attached to the body in such a way that their hinder and lateral margins are free; the latter, which is 3-1 mm. broad, carries three pairs of hooks ; there are two stiff supporting lamelle, which obviously prevent the suckers from being torn off. All the three sucking dises consist of a cuticle, which is much stronger on the dorsal than on the ventral surface, and of a well-developed dorsoventral muscular mass, in which separate cells are imbedded ; the parenchyma is feebly developed, is fibrous, and contains no nuclei. The three pairs of hooks vary a good deal in structure ; the most anterior pair is sur- rounded by two tendons which lie in a sheath where they can work backwards and forwards. While the hooks of most Trematodes and Cestodes are organs which serve for attachment, those of this form are clearly organs which are adapted to loose the parasite from its place of attachment ; the median long hooks have the function of surrounding the free margin of a fish’s scale. These hooks are of a horny nature
The cuticle consists of a plexiform fundamental tissue, the spaces in which are filled by rods of various sizes, better developed on the dorsal than on the ventral surface, and giving a villous appearance. In the dorsal cuticle there are also numerous rounded glands, which probably secrete mucus. ‘The muscles of the cortical layer must be distinguished from those of the parenchyma; they are either longitudinal, circular, or diagonal in direction. The muscles of the parenchyma are uncommonly strong, and are remarkable for passing through the testes, ovary, and shell-gland.
The mouth is a large, almost spherical organ, 0:78 mm. in diameter ; while it is well developed, the intestine is very feeble, and we must suppose, therefore, that the ingestion of food requires much greater strength than its propulsion and absorption. A rich vascular system traverses the whole body ; it is formed of two large longitudinal trunks which divide the body into three nearly equal thirds; posteriorly they unite to form a cylindrical pulsatory vesicle which is covered by the posterior sucking disc, and opens by a foramen caudale. Anteriorly they widen out into large vesicles which vary considerably in their condition of contraction ; one is almost always much larger than the other, and both
* Boll. Soc. Adriat. Sci. Nat., xi. (1889) pp. 23-30 (2 pls.). + T.c, pp. 60-74. ¢ Archiv f. Mikr. Anat., xxxiii. (1889) pp. 163-80 (2 pls.).
522 SUMMARY OF CURRENT RESEARCHES RELATING TO
open bya small cleft outwards. Secondary are given off from the primary trunks, and all the trunks form anastomoses with one another.
The brain has the form of a kidney-shaped group of ganglionie cells which lies just above the mouth; four ocelli may be noticed in it; a second group of cells lying just behind the mouth may be called the cesophageal ganglion. Four to six nerves are given off anteriorly from the brain; four nerves run along the ventral surface of the body; these nerves are easily recognized in stained transverse sections of the body ; a third pair of nerves, which are much thinner, are placed on the dorsal surface. In the middle of the brain lie four ocelli; each of these con- sists of a spherical lens surrounded by a layer of pigment; on the free ‘side of each is a small highly refractive spherule which, possibly, acts like the condenser of a Microscope. These ocelli are remarkable for lying not in the cuticle, but in the centre of the brain, so that they are covered externally by a layer 0:14 mm. thick. It seems clear, therefore, that they cannot have the function of recognizing images, but can only be able to distinguish light from darkness, as is the case with the eyes of various Vertebrates which are covered by the skin.
The body-parenchyma, which stains feebly, is not cellular in structure, but consists of a fine fibrous ground-substance, in which are rounded or angular nuclei, 0-02 mm. in size. There is one ovary, and a pair of testicles ; the seminal vesicle has very strong walls; the cirrus is large and spindle-shaped, and lies to the left of, and just beneath the mouth. The ovary is rounded, and is placed just in front of the testes; super- ficially the two organs are very much alike. The vitellaria are very widely distributed in the body, and lie in a dorsal and a ventral plane ; the ootyp is spindle-shaped, and in it there is always found only one egg. The shell-cland is of great extent, and consists of a large number of pyriform glands with long efferent ducts. The ova are rhomboidal, irregular, or triangular in form ; at the hinder end there is a filamentar appendage of varying length. There is no canal of Laurer; a com- parison of various forms shows that by this term, organs of various functions are spoken of. Like the two other species of Phylline, the development of P. Hendorfii is unknown; it is doubtless monogenetic, and its embryos swim about in water by the aid of an investment of cilia.
The author points out the differences between the three species, and concludes with enumerating the generic characters of Phylline.
Nervous System of Amphiptyches.*— Dr. F. 8. Monticelli has, in the course of his researches on Amphiptyches, elucidated the nature of the nervous system, which has hitherto been known only through a brief notice by Wagener. It consists essentially of two lateral ganglionic swellings, situated in the anterior portion of the body, and united by a transverse commissure. Four nerves, two anterior and two posterior, rise from the two ganglionic swellings. The whole system, of which the details are described, lies rather towards the ventral surface. Morpho- logically the system agrees with the general cestode type, and closely resembles that of the simpler Cestodes, especially that described by Lang in Amphilina foliacea Wagen.
Cercaria setifera.jt—Dr. F. 8. Monticelli has a preliminary notice on a Cercaria with a long tail and lateral bristles, which occurs in the
* Zool. Anzeig., xii. (1889) pp. 142-4. + Bol. Soc. Nat. Napoli, ii. (1888) pp. 193-9.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC, 523
Gulf of Naples, sometimes free-swimming, but more frequently on pelagic Ceelenterates, Tunicates, worms, and molluscs. He identities it with Cercaria setifera Miller and with the Cercaria echinocerca of de Filippi, and considers it as not improbably related to a form of Disto- mum found in Beroé. The characteristics of the species are shortly described.
Structure of Solenophorus.*—Signor C. Crety has particularly devoted himself to the nervous system of S. megacephalus, in regard to which the results of Moniez, Roboz, and Griesbach are not in agree- ment. Two longitudinal nerves extend down the body; these are united in a commissure and ganglionic centre in the head. The histology is discussed, and the entire system regarded as closely resembling that of
Bothriocephalus latus as described by Niemiec.
5. Incertz Sedis.
Rotifers Parasitic in Sphagnum.t—Mr. W. Milne describes two species of Rotifers found living inside the cells of Sphagnum, and thus confirms observations made nearly forty years ago by Roeper and Morren. These observers supposed the animal they saw to be Rotifer vulgaris, but Mr. Milne designates what he observed as Macrotrachela roeperi sp. n. and M. reclusa sp.n. In three different gatherings of the Sphagnum, at considerable intervals of time, from the same locality, both species were found abundantly. The observer believes the distribution of the rotifers in the Sphagnum to be mainly effected by the external openings in the cells, yet one of the forms observed forcing its way out took two or three minutes to escape through the opening. In one case, two adults and an egg were seen in the same cell, which was possibly the result of a breakage between two adjacent cells. There is of course no real parasitism, but the shelter afforded is doubtless advantageous.
American Rotifera.{—Dr. D. 8. Kellicott gives a partial list of the Rotifera of Shiawassee river at Corunna, Michigan. From the brief examination he was able to make, he was led to the conclusion that the rotiferal fauna of inland America is abundant, and that the species are largely identical with those of Europe, even to a greater degree than in the case of Infusoria. The author adopts the classification of Hudson and Gosse.
The new forms described are :—(1) Limnias shiawasseénsis ; it has very much longer antenne then L. annulatus, and has different horny processes and tube ; (2) Wcistes mucicola, which dwells in tubes made in the mucilaginous matrix of the common Alga Gloiotricha pisum ; (8) Callidina socials, found parasitic on the larva of the beetle Psephenus Lecontei, has a corona which is relatively wider than that of C. parasitica, and its antenna does not end in three lobes; and (4) Sacculus hyalinus which is much smaller then 8S. viridis. In all, fifty species are enumerated in this list, so the percentage of new forms is very small.
Tornaria in British Seas.S—Mr. G. C. Bourne gives an account of the well-known pelagic larva of Balanoglossus, which was for the first
* Boll. Soc. Nat. Napoli, ii. (1888) pp. 124-30. + Proc. Phil. Soc. Glasgow, 1889, 6 pp. (1 pl.). t Proc. Amer. Soc. Micr., x. (1888) pp. 84-96. § Journ. Marine Biol. Assoc., i. (1889) pp. 63-8 (2 pls.).
524 SUMMARY OF CURRENT RESEARCHES RELATING TO
time found last year in British Seas. Its discoverer was Mr. Weldon, who was working at the Plymouth Laboratory.
The smallest larve were 0:33 mm. in length, and it would seem that the posterior division of the gut is not a proctodeum, but that the blastopore persists as the anus without being pushed further inwards by a secondary invagination of ectoderm. In later stages all the characters of a Tornaria were found exhibited. The anterior body, which is pro- bably formed from the ameeboid cells found in the earlier larva, is connected by a muscular thread with the now conspicuous apical sense- organ. A perfect Tornaria was as much as a millimetre in length, but individuals vary greatly in this respect. Hach ciliated cell is long and columuar, slightly contracted in the middle of its length, and has a large nucleus ; the cilia can be traced as fine fibrille inwards as far as the nucleus, but the author was unable to determine whether or no they entered it. The “heart,” as some authors call it, appears as a vesicle lying just above and to one side of the proboscis pore.
The central portion of the apical sense-organ is composed of columnar sense-cells bearing cilia; on it there are larger cells surrounding a pair of deeply pigmented pits—the eye-spots of previous authors. Beneath the sensory cells is a thin layer of nerve-fibres.
Specimens of the larve at later stages were never found, and it is very probable that Tornaria ceases to lead a pelagic life, sinks to the bottom, and undergoes its further development there.
Echinodermata.
Ludwig’s Echinodermata.*—Prof. H. Ludwig has issued another part of his work ; the description of the calcareous bodies is continued and completed. The general ground-form of these bodies is, in the Dendrochirota, derived from an X-shaped rudiment, which has been developed by the forking of the ends of a short rod. The same is true of the “stools” of the Aspidochirota, and the four-armed calcareous bodies of the Elasipoda and some Aspidochirota, as well as of the fenestrated plates of the Molpadide, and the anchor-plates of the Synaptide. The anchors of these last may be referable to the same scheme, but the “ wheels” are more difficult to explain. Another kind of calcareous body which is difficult to explain are the “tables” of the Aspidochirota, which are symmetrically perforated, though there can be little doubt but that they will be found to be derived from the bifureating rod. Theangle at which this forking takes place is, as a rule, 120 degrees. The concentrically striated bodies which are found in Trochostoma and Ankyroderma appear to be special bodies, agreeing only with the rest in that they consist of an inorganic substance.
The musculature of the bedy-wall and the histological characters of muscle are next considered. In dealing with the nervous system Prof. Ludwig gives a diagram to show the relations of the parts. The central nervous system consists of a circular and of radial nerves. The peri- pheral nerves derived from the former of these are the tentacular, the integumentary nerves of the oral disc, and that of the pharynx ; with the last the plexus on the stomach and on the small intestine may be con- nected. ‘The peripheral nerves derived from the radial are those of the
* Byronn’s Klassen u. Ordnungen, ii. 3. Hchinodermata, by Dr. H. Ludwig, Leipzig and Heidelberg, 1889, pp. 49-80 (pls. 1-5).
ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 525
foot-suckers, of the skin, of the muscles, of the nerves to the closing muscu- lature of the cloaca, and of those to the mesentery of the hinder end of the body. In the third place there are sensory or terminal organs. The tentacular nerves serve the sensory plates of the tentacles of the Aspido- and Dendrochirota, the bud-like sensory organs, and the tactile papille of the tentacles of the Synaptide. The sensory cells of the skin are innervated by the tegumentary nerves; those of the foot-suckers and ambulacral papille by the nerves that go to them, while the tegumentary nerves supply the tactile papille of the skin of the Synaptide and the sensory cells of the skin. When auditory vesicles are present the radial nerves give off auditory trunks.
Anatomy of Ophiuroids and Crinoids.*—Dr. O. Hamann continues his account of the morphology of Echinoderms by treating of the anatomy of Ophiuroids and Crinoids. In summarizing his results generally he commences with the ambulacral nervous system; this is found in all Echinoderms, lying, in Asterids and Crinoids, always in the ectoderm, and in others in the cutis, where itis generally surrounded by schizoccel spaces. In Crinoids the cesophageal ring is lost. The facts that the ambulacral nerve-trunks of Ophiuroids are jointed, and that there are ganglia in the dorsal as well as the ventral cells, are of great importance. The ambulacral and mesodermal nervous system of the Crinoids and its origin are next considered. This system consists of a mesodermal pentagonal nerve-ring, and, in each arm, of two longitudinal nerves, and the question arises, did these parts arise separately or is their present condition a secondary one? The oral-mesodermal portion is regarded as being derived from the ambulacral nervous system of Crinoids, support for this view being found in the fact that the latter is only preserved in rudiment in the epithelium; this ambulacral system has no central organ, and the nerves in the epithelium are very poorly developed as compared with the homologous nerves of other Echinoderms. The ectodermal portion, therefore, has passed from the ectoderm into the mesoderm, and its branches have been developed in the same way as the peculiar nerves of Ophiurids, which arise at definite intervals from the ambulacral nerves and form intervertebral nerve-branches. But while the latter have retained connection with their point of origin, they have lost it in the Crinoids, Further evidence in support of this view is given by the agreement in structure which the three parts present. In all three there are the same nerve-fibrils and ganglionic cells. While there is no direct connection between the epithelial, ambulacral nervous system and the other parts, there is such between the dorsal and ventral portions.
The peripheral nervous system and the sensory organs are next considered ; in the Crinoids there are nerve-endings in the epithelium of the skin similar to those found in Asterids and Holothurians, as also the sensory buds on the tentacles, which have been recognized by Jickeli as sense-organs. In the Ophiurids, as the physiological investigations of Preyer have conclusively shown, the peripheral nervous system is exceedingly well developed; special sensory organs may be found in large numbers on the tentacles of Ophiothri#, and the nerve-endings in the epithelium are similar to those of Crinoids. In all groups there is a nervous system in the epithelium of the enteric tract.
* Jenaische Zeitschr. f. Naturwiss., xxiii. (1889) pp. 233-388 (12 pls.). 1889. 20
526 SUMMARY OF CURRENT RESEARCHES RELATING TO
The water-vascular system has a similar character in all groups, but the Crinoids have no madreporite, and their pore-canals do not open directly into the stone-canal, but into superficially placed cavities of the enterocel. The valvular arrangements of this system are of great interest, but they are wanting in Ophiuroids and Crinoids, where they are replaced by transversely disposed muscular fibres which traverse the lumen of the vessels.
All the groups are provided with genital tubes; in Crinoids they are placed in the arms, in Ophiuroids in the dorsal wall and in the walls of the burse, and in Asteroids and Hchinoids in the dorsal wall of the disc. The several groups present differences in the place of maturation of the primordial germ-cells, for in Crinoids they ripen in the pinnules, and in Ophiurids on the walls of the burs.
In addition to smooth and transversely striated muscular fibres, there are in Ophiuroids peculiar obliquely striated fibres. Hpithelio-muscular cells have been found in Holothurians, Asteroids, and Crinoids. The musculature is partly of epithelial and partly of mesenchymatous origin. The Crinoids are remarkable for spindle-shaped muscular fibres, which are found in the arms as well as in the pinnules and cirri.
The glandular organ or so-called heart is not the central organ of the blood-lacuna-system; muscular fibres are never found in its walls. It is impossible to say at present what the function of this organ is; the only thing which can be said with certainty is that the organ has a glandular structure. The connection between it and the genital tubes, which is to be seen in Asteroids and Crinoids, is of significance.
With regard to the structures of the schizoccel, it is to be noted that there is a very well developed cavitary system in Asteroids which has the form of clefts and spaces in the connective substance; in the Ophiuroids they are less extensive, and in the Crinoids they are repre- sented by the longitudinal canals which lie beneath the ambulacral nerves.
The author’s determination to deal with the phylogeny of the Echinodermata has wavered as his work proceeded, for he has been led to see of how subjective a nature such a representation is. Of one point only is he firmly convinced, and that is, the Asterids are connected with the Echinids, and that the latter may be derived from the former. The Holothurians appear to be forms which have undergone degenera- tion; many characters speak to their derivation from Hchinids; the Crinoids seem to be the most highly organized forms, and with the Ophiuroids form a group which have no specially close relation to the others, save that they are all derived from an ancestor in which a water-vascular system, a coelom, an ectodermal nervous system and definite calcareous plates were already developed. With regard to Semon’s recent attempt to map out the phylogeny of the group, Dr. Hamann remarks that, in the present state of our knowledge of the development of Echinoderms, it is too early to speak definitely of a Pentactula-stage of a Pentactezea; nor does he think it correct to say that there is such a stage in all groups, for the structures which have been spoken of as one and the same stage are different, and show undoubted modifications. Further objections are raised to the views of Semon, and it is, in conclusion, suggested that weight should still be attached to the homologies of the calcareous plates.
ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 527
Nervous System of Ophiurids.*—Dr. C. F. Jickeli has extended - his observations on the nervous system of Echinoderms to Ophiurids. If a number of sections of an arm be examined, four nervous systems will be found extending in a longitudinal direction—there is the ambulacral nerve of authors, which Dr. Jickeli proposes to speak of as the ventral radial system; placed on this, and separated from it by a structureless Jamella, is the paired ganglionic chain of Lange which it is proposed to call the median radial system; on the dorsal wall of the perihemal canal isa paired ganglionic chain, which may be distinguished as the dorsal radial system. Two ganglionic chains lie between the dorsal and ventral muscle on the external edge of the ambulacral plate ; this is the lateral radial system.
The ventral radial system gives off on either side a nerve which passes up the wall of the perihemal canal, and fuses with the neighbour- ing cord of the dorsal radial system; a branch on either side, which is continued laterally, gives off a branch into the muscle between the adambulacral and basal plate, and breaks up within the former into several branches; of these the innermost passes to the dorsal plate, while the other branches enter an adambulacral papilla; this may be called the adambulacral nerve. Belonging also to the ventral radial system is a nerve on either side for the ambulacral pedicels; this forms a subepithelial sheath around the whole pedicle, and becomes con- solidated on its adoral side into a strong cord which is circular in trans- verse section.
The median radial system gives off a branch on either side which innervates the ventral interambulacral muscle, and another which, like it, arises from a ganglion, and innervates the dorsal interambu- lacral muscle. The dorsal radial system gives off branches on either side, one of which ends in a ganglion of the lateral radial system, another which becomes connected with the nerve for the ventral inter- vertebral muscle, and others which unite with the dorsal. The three pairs of ganglia of the dorsal radial system are connected by transverse commissures, but the author could not find the one described by Lange.
In all, each ambulacral segment has nine pairs of nerves; in the formation of the oral ring, the ventral, median, and dorsal radial systems take part, and this therefore consists of three different rings. In addition to these, another is formed by the lateral system; as it lies more externally than the others, it may be called the outer oral ring, while the oral ring of previous authors is to be called the inner oral ring. From this last the ventral ring gives off branches to each of the two oral pedicels, and a strong branch, which, in its somewhat complex course, gives off a number of branches ; all these are connected with the corresponding branches of the adjoining rays. With them the bifurcate branches of a third trunk become connected. The median and dorsal rings combine to give a trunk which sends nerves to the adoral side of the outer interradial muscle. Branches are given off dorsally from the dorsal nerve-ring which appear to innervate the water-vascular ring and the Polian vesicles. Strong nerves are given off at regular distances to the “lips”; these appear to be processes from all the three systems which compose the inner oral ring. No indications were seen of the
* Zool. Anzeig., xii. (i889) pp. 213-8. 202
528 SUMMARY OF CURRENT RESEARCHES RELATING TO
subepithelial enteric plexus, which has been made out by the author in Crinoids and Asteroids.
Morphology of Crinoids.*—Dr. O. Hamann, in a preliminary com- munication, deals with the nervous system of Crinoids. The epithelial portion consists of the subepithelial plexus described by Ludwig and others, and of the central cesophageal ring ; it corresponds to the ceso- phageal ring and ambulacral nerves of other recent Echinoderms, which are partly epithelial and partly mesodermal in position. In Crinoids the epithelium of the ambulacral grooves is considerably thickened, and consists of the same elements as in a starfish. In both there are epithelial nerve-fibres with bi- and multipolar ganglionic cells; they have not lost their connection with the epithelium of the body; this nervous system has no central ring. The cpithelium of the grooves is made up of sensory and supporting cells, and the processes of the latter traverse the nerve-fibrous ring vertically. In each tentacle there is a nervous band which innervates the sensory papille.
Another system of nerves is placed in the connective substance, and to this belongs the fibrous mass placed around the chambered organ with its nerve-trunks, which run along the dorsal side of the arm. Another part of it is ventral in position, and has its own central organ. The two portions of this mesodermal nervous system are connected with one another. The ventral or oral part is divisible into a central organ, an cesophageal ring, and the nerves given off from it; some of these nerve-trunks have been described by Carpenter as a periambulacral network. The nerve-fibrils of the ring have a concentric course, and the number of nerves given off is very large. Some of these take a dorsal or aboral direction and branch in the mesenteries and bands of the ccelom, and on the organs that lie therein. Other nerves pass into the circumoral tentacles. Those that are of the greatest interest are those which enter into definite relations with the water-vessels; these are, at first, five, and they bifurcate and pass into the oral body-wall of the arms. Each water-vessel is accompanied on either side by a nerye-trunk, so that they are twenty nerve-bands in the ten arms, to the tips of which they may be traced. They likewise pass with the branches of the water-vessels into the pinnule.
The dorsal or aboral portion of the mesodermal nervous system has likewise a central organ, and the course of the fibres which compose it is complicated. It gives off solid nerve-trunks into the arms, and never hollow tubes as some observers have asserted. The trunks in the arms give off branches from four opposite points ; some of these go to the flexor muscles, and others, after much branching, to the dorsal epithelium. Between every two groups of muscles, nerves pass out which go almost directly to the oral body-wall, where they become connected with the oral pair of longitudinal nerves which belong to the oral part of this mesodermal nervous system.
Both the epithelially and mesodermally placed systems are com- posed of very fine fibres, which generally run parallel and in cross section appear dotted, and of ganglionic cells of various types. The nerves of the cirri are regarded as special nerves; they are the only vascular nerves found in Crinoids.
In addition to the sensory papille of the skin there are nerve-end-
* Nacbr. K. Gesell. Wiss. Gottingen, 1888, pp. 127-31.
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 529
organs scattered over the whole surface of the arms and disc; these are made up of epithelial groove-cells.
The author regards the presence of two nervous systems as, in con- junction with the other structural characters of Crinoids, indicating that this is the most highly developed group of Echinoderms.
Large Starfish.*—Prof. F. Jeffrey Bell describes a remarkably large specimen of Luidia Savignii from Mauritius, which has nine arms, none of which are injured or bear signs of having been repaired during life. The disc is 95 mm. in diameter, and the longest arms measure 370 mm., and the shortest 350 mm., so that the span is about 27 inches.
Variation in Ophiura panamensis and 0. teres.,—Mr. J. E. Ives has an interesting note on the variations exhibited by examples of these two Ophiurids ; O. panamensis exhibits a very great variety of colour pattern, due probably to the wide range of the species; the darker varieties are found in the more northern parts of its area of distri- bution.
Ceelenterata.
Pennatulida of Mergui Archipelago.t—Prof. A. Milnes Marshall and Dr. G. H. Fowler report on the Pennatulids collected by Dr. J. Anderson. Representatives of five genera and ten species, of the latter of which two are new, were obtained. The numerous examples of both Pteroeides Lacazii and P. chinense exhibit great variability, and in each case these may be arranged in two groups; the same is true, also, of P. espert. Virgularia Rumphii has colonies which may be as much as 900 mm. long; the swelling at the end of the stalk is shown to depend on the state of contraction of the individual and is a character of no practical value in classification. Fifteen specimens of this genus are referred to a new species which is called V. prolifera ; all show the truncation of the upper end of the rachis that is so characteristic a feature of the genus. The other new species in the collection— Policella tenuis—was represented by a single example 252 mm. in length ; it can easily be distinguished from P. mawillaris which was collected with it.
Lebrunia neglecta.S—Prof. J. P. M‘Murrick has a note on this incompletely known Actiniarian. Its original describers, Duchassaing and Michelotti, were wrong in saying that it has five dichotomously branched processes, for it has six; these are, to use the recent nomencla- ture of R. Hertwig, pseudotentacles. Allied to this form are, apparently, the deep-sea Actinie, Ophiodiscus annulatus and O. sulcatus, described by Hertwig from the ‘Challenger’ collections, but they are not con- generic. This is proved by the absence in Lebrunia of a circular muscle and of specialized gonophoric mesenteries. It belongs to Hertwig’s tribe Hexactiniz, the three divisions of which formed by Andres appear to be natural; to these the author proposes to add a fourth which he calls Dendromeline. It would include Lebrunia and probably Ophio- discus, and may be characterized by the presence of marginal tentacles arranged in cycles, and by the pessession of pseudotentacles arising from the column-wall. Further details are promised.
* Ann-and Mag. Nat. Hist., iii. (1889) pp. 422-3.
+ Proc. Acad. Nat. Sci. Philad., 1889, pp. 76-7.
{ Journ. Linn. Soc. Lond., xxi. (1889) pp. 267-86 (2 pls.). § Zool. Anzeig., xii. (1859) pp. 38-40.
530 SUMMARY OF CURRENT RESEARCHES RELATING TO
Remarkable Actinian.*—Dr. C. P. Sluiter corrects an error which he committed in an article on two remarkable Gephyrea in vol. xlviii. (p. 233) of the Nat. Tijdschr. voor Nederl. Indié. He now sees that Diphthera octoplax is an Actinian. He urges that he had never before seen an Actinian of the kind, and that no one who saw it alive would hesitate to call it one of the Phascolosomata. ‘The anterior end of the body looks like a proboscis and acts energetically and not slowly. The histological characters of the integument are much like those of a Sipun- culid. The creature should, apparently, be placed in the genus Hdwardsia.
Caryophyllia rugosa.t—Herr G. v. Koch has made an examination of the structure of Caryophyllia rugosa. This form has especial interest from the fact that it was described by Moseley as having the septa arranged in octameral fashion. With this Herr v. Koch cannot agree, as he finds that there are at first six septa of the first order, which are followed by six of the second. Both of these sets are arranged quite symmetrically. When the septa of the third order appear there is some irregularity, for those in two adjoining sections appear earlier than those in the rest, while, at the same time, the interjacent septa of the second order grow more rapidly than their homologues in the four other sectors. There are thus gradually developed eight larger septa (six of the first and two of the second order), and eight smaller septa (four of the second and four of the third order), so that the coral comes to look as though it were octamerous. When the third cycle is complete, the number of | septa is again of the hexameral type, but soon afterwards eight septa of the fourth order appear in the already mentioned two sectors. The whole number is thus raised to thirty-two, and as this is not increased the octameral type again becomes apparent. We have here, therefore, - an interesting example of a coral which, when adult, is regularly octamerous, being in its youth six-rayed.
Semzostomatous and Rhizostomatous Meduse.{—Dr. E. Vanhéffen describes the Medusze of these orders collected on the ‘ Vettor Pisani’ expedition. Of Semzostomata, six new species are described— Pelagia neglecta, P. crassa, P. minuta, Chrysaora chinensis, Desmonema chierchiana, and Aurelia dubia ; seven others are revised ; and a systematic review is taken of all the known species in the above genera. Of Rhizostomata, six new forms were discovered— Cassiopeia picta n. sp., Loborhiza orna- iella g. et sp. n., Stomolophus chunii nu. sp., Rhizostoma hispidum ux. sp., Mastigias orsini n. sp., and Desmostoma gracile g.etsp.u. After deserib- ing these forms, the author takes a systematic survey of known Rhizo- stomata. The third part of his memoir is devoted to a survey of the geographical distribution with which a map is given. The two orders differ greatly in their range. Thus in the Red Sea, Semzostomata are absent, but Rhizostomata are abundant; on the Pacific coast of North America the reverse is true. From similar facts Dr. Vanhéffen con- cludes that the Rhizostomata usually prefer warmer waters, while the Semzostomata are more abundantly represented in temperate zones.
Siphonophora of Canary Islands.§—Prof. C. Chun reports that he has discovered a considerable number of new species of Siphonophora off
* Zool. Anzeig., xii. (1889) pp. 47-8. + Morphol. Jahrb., xv. (1889) pp. 10-20.
{ Bibliotheca Zool. (Leuckart and Chun), Heft 3 (1889) 52 pp., 6 pls. and map.
§ SB. K. Akad. Wiss. Berlin, 1888, pp. 1141-73. Ann. and Mag. Nat. Hist., iii. (1889) pp. 214-46,
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 581
the Canary Islands. Some of them are interesting because of their peculiarities of structure, and others because they are forms which unite groups which hitherto appeared to be isolated. Before com- mencing the detailed account of the species which he observed, Prof. Chun makes some remarks on the recently published views of Prof. Haeckel.
With regard to the proposed division of the Siphonophora into two subclasses, Prof. Chun urges that Haeckel has founded his speculations on two larval forms of very different morphological value. The Velel- lidas certainly represent not only the most complicated in structure, but also the most divergent of the Physophoride; but there is no feature in their organization which cannot be explained by gradual adaptation to an existence at the surface of the sea. The author would propose to divide the order Physophoride into two suborders, one of which would include all with an unchambered pneumatophore functioning as a gas- gland (Haplophyse), while in the other there would be the (partially) air- breathing Velellide (Trachophyse) with a chambered pneumatophore, stigmata, and trachee. Prof. Chun also urges reasons against Haeckel’s Medusa-theory of the morphology of the Siphonophora.
Among the new forms described are Doramasia g. n. for Ersea Bojani Esch., and D. picta sp. n.; in it the nectocalyx is diphyidiform, slender, with a long apex to the subumbrella drawn out in the form of a tube, and the Eudoxiz have special nectocalyces; in Halopyramis g. n. the nectocalyx forms a broad, four-sided, tetragonal pyramid, the hydreecium is infundibuliform, with a projecting denticulate margin, the oil-receptacle is very large and situated in the axis of the pyramid, the subumbrella is excentric, the stem is abbreviated and not protrusible, while the Eudoxiz have no special nectocalyx, and become free as in Cuboides.
The family Amphicaryonide is formed for Amphicaryon g. n.; in it the nectocalyces have a rounded exumbrella, and the stem is metamor- phosed into a disc ; the bud-groups are set free as diplophysiform Eudoxiz. The Stephanophyide contain the new genus Stephanophyes, and are defined as Calycophoride with four nectocalyces placed like a wreath in the same plane, and with heteromorphous tentacles. In the internodes of S. superba sp. n., the heteromorphous tentacles which have been as yet found only in Stephanophyes among the Calycophoride, are found placed. This species is, of all the Siphonophora known to the author, the most delicate, and one of the most magnificent. It is perfectly trans- parent, and may be as much as 18 inches long. “The graceful play of its heteromorphous tentacles, the energetic pumping movements of the large calyces and the numerous special nectocalyces, the bright red colouring of the knobbed fluid vessels with their shining oil-drops, the delicate rosy or emerald-green shimmer of the gastric polyps, the perfect transparency of the large globular ova, and the delicate flesh-tint of the male manubria all combine to mark Stephanophyes as one of the most splendid objects among pelagic animals.” This interesting form passes through a remarkable metamorphosis. The youngest specimens, which are perfectly transparent, and therefore easily escape even the practised eye, display the characters of the genus Lilyopsis ; they possess two nectocalyces with the fluid-canal only once divided dichotomously, and are completely devoid of the heteromorphous tentacles found in the internodes of older groups. This new genus unites the Prayide and
532 SUMMARY OF CURRENT RESEARCHES RELATING TO
Polyphyide, and has some points of structural resemblance to the Physophoride.
Passing from the Calycophoride to the Physophoride, the author points out the many resemblances which connect the two orders. In the embryos of both a heteromorphous rudimentary nectocalyx is formed, which is lost in most if not all Calycophoride, while in the Physo- phoride it becomes converted into the pneumatophore. In the more highly organized Calycophoridee there are a number of calyces of the same form, the close concentration of the buds into Eudoxia-groups is given up, aud in some species the stem is transformed, as in many Physophoride, into a gemmiparous disc. Here, then, we have a series of characters which seem.to indicate that the Physophoride took their origin, if not from the Stephanophyide or Polyphyide, at least from a root common to the two orders. Stephanophyes with its heteromorphous tentacles shadows forth a condition which has hitherto been regarded as an exclusive characteristic of the Physophoride.
The morphology of Halistemma pictum has been closely examined, and it is shown that the order of gemmation is reguiar; the author leaves it to Prof. Haeckel to reconcile this fact with his theory of the multiplication and dislocation of the medusa-organ on the Siphonophoran stock. In the post-embryonic development of Crystallodes rigidum a point of great interest is the peculiar formation of the larval tentacles. Haeckel thinks that the cnidaria of the primary tentacle are directly developed into the definitive cnidaria. Observation, however, has shown that they are larval structures, which, later on, are succeeded by hetero- morphous organs. The nectostyles of some gigantic examples of Forskalia ophiura were a foot in length.
New Athorybia.*—Mr. J. Walter Fewkes describes Athorybia cali- fornica sp. u., which differs from any known species in the form of its tentacular knobs. 'The sacculus, which ordinarily forms a bell-shaped covering, is much modified and reduced in size; it is a globular or hemispherical enlargement which shows the spongy cellular walls which have been described in the knobs of the genus Rhizophysa. If the question were raised as to whether this new form was not the young of some long-stemmed Physophore, like Agalma, the author confesses that it may be so. But if larval, this new form is different from any larva yet described. The sexual bodies are but little developed, and, even if they were well so, that fact alone would not prove the maturity of the animal, for among the Physophores there are known genera in which the sexual products are matured before the adult form is reached.
Eyes of Acalephe.t—Herr W. Schewiakoff has examined the eyes of several Acalephe. He finds that there is great diversity of structure, and that they are so far genetically connected that the simpler only represent developmental stages of such as are more highly organized. In the simplest cases the eyes have the form of a pigment-spot, as in Aurelia aurita. These spots are formed of cells, the pigment- and the optic-cells, with two different functions, which are performed in definite areas of the ectoderm, the so-called sensory epithelium. These are the districts from which the light-perceiving spots are developed.
The next step in the further complication of the optic organ consists
* Ann, and Mag. Nat. Hist., iii. (1889) pp. 207-10 (1 pl.). + Morphol. Jahrb., xv. (1889) pp. 21-60 (3 pls.)
ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 5338
in the sensory epithelium, which is differentiated for the perception of light, sinking into the body and so giving rise to the so-called optic pits ; such organs may be found in Charybdea marsupialis, and in their com- position they differ not at all from the superficial pigment-eyes. Their depression is not only a sign of the more definite localization of the per- cipient spots, but a protective arrangement. Still deeper depression leads to the so-called goblet-eyes, which are first met with in the proximal goblet-eyes of Charybdea ; in conjunction with this depression there is the development of a new constituent of the eye—the so-called vitreous body which is differentiated off from the pigment-cells ; it closes the eye cup externally and fills its cavity. A further, though less con- siderable, complication is found in the distal goblet-eyes of Charybdea, where the invagination of the sensory epithelium forms a secondary outgrowth. In connection with this we meet with a differentiation of the cellular elements which form the wall of the eye; the cells abutting on the proximal wall-of the optic cup are formed of pigment-cells, and this arrangement is functionally that of an iris, for by it the lateral rays of light are cut off.
The goblet-eyes of Aurelia are developed on quite a different type. They are not formed, like the other eyes of jelly-fishes, by the invagina- tion of the sensory epithelium, but of the endoderm and, possibly, of the supporting lamella; the goblet-wall is, consequently, formed of altered endodermal cells which are filled with pigment. This invagination of the endoderm is followed by that of the optic cells of the ectoderm. As a result of this interesting mode of origin it follows that the nerve-fibres do not arise from inside but from outside the optic cells, and are con- nected with their outer ends; the free ends appear, therefore, to be turned away from the light, which must pass through the whole of the nerve-layers before it reaches the ends of the optic cells. This relation of parts is not unlike that which obtains in the eyes of Onchidia, Lamel- libranchs, Arachnids, and Vertebrates.
The causes, however, are quite different, and the goblet-eyes of Aurelia must therefore be regarded as belonging to a special type which cannot be directly compared with any yet known type of eye; there is, indeed, a certain resemblance to the eyes of the Turbellaria.
The structure of the lens-eyes of Charybdea, which attain a very high grade of development, is very interesting. They are derived from goblet-eyes, the goblet narrowing at its outer end and becoming con- stricted off from the body-epithelium. The orifice becomes closed, and an optic vesicle completely shut off from the exterior becomes developed ; this is surrounded by the afferent nervous layer as far as its superficial part. In addition to this the body-epithelium grows together at the point where the invagination has taken place, and forms a thin trans- parent layer—the so-called cornea. Simultaneously with this there is a differentiation of the cells which form the outwardly directed wall of the primitive optic vesicle. These increase greatly in length, and, later on, form the spherical lens which projects into the optic vesicle, and occupies a large part of it. The cells of the vesicle at the periphery of the lens become differentiated into the so-called iris. The proximal lens-eye no doubt arises in the same way as the distal, but the proximally directed and not the outer wall of the vesicle becomes differentiated into the lens; a gelatinous stalk is formed which carries the lens.
This mode of origin and the peculiarities of these eyes of Charybdea,
534 SUMMARY OF CURRENT RESEARCHES RELATING TO
cannot be compared with any known type of eye. In some, the structureless lens is developed within the optic vesicle, and is a secre- tion-product of the cells which compose it; such eyes are to be found in Gastropods, Cephalopods, Annelids, and in Peripatus. In others the lens is developed outside the primary optic vesicle, and is either structureless as in many Arthropods, or composed of cells, as in the dorsal eyes of Onchidium, and the eyes of Lamellibranchs, and Verte- brates. The vestigial parietal eye of some Reptiles appears to have the same type of lens as the eyes of Charybdea, for it is formed from the outer wall of the optic vesicle. There appear, then, to be three types of lens-eyes.
Porifera.
Cliona.*—Dr. J. Leidy gives a short and interesting account of this boring sponge, and describes a new form from the coast of Florida, which he proposes to call C. phallica ; it has an opening at its summit which is closed when the sponge is disturbed.
Protozoa.
Functional Differentiations in Unicellular Beings.;—M. Fabre- Domergue replies to some criticisms of M. Maupas as to the existence of functional differentiations in unicellular organisms. Taking Didinium nasutum, he urges that at the moment when prey is ingested, there is a clear axial tract, resulting from the formation of a canal which extends from the mouth to the anus ; the existence of this canal is confirmed by the retraction of its wall under the influence of iodine, and by the course taken by the food which always goes straight from mouth to anus. M. Maupas denies the existence of this canal because it has no proper walls, but he likewise, it is true, denies that an air-bubble has walls. Functional differentiation is still better marked in the excretory system ; the most striking example is the remarkable contractile plexus of Cyrto- stomum, but it is only the most perfect expression of a structure which exists in all Ciliata, and traces of which may be found in a large number of forms.
Maupas’ Researches on Ciliata.{-—Prof. A. Gruber does not accept all the general conclusions which Maupas has drawn from his re- searches on ciliated Infusorians. (1) The multiplication has been shown to occur in asexual cycles, which end in degeneration and death if conjugation does not take place. Therefore, Maupas maintains, the doctrine of the immortality of the Protozoa must be abandoned. But the conjugation always occurs in the natural conditions of life, so that Maupas’ objection is not after all serious. It is only necessary to add to Weismann’s original statement a saving clause as to the necessity of conjugation. (2) Maupas opposes Weismann in regard to the equality _ of the products of division. After 50-100 divisions the products are both morphologically and physiologically different. But the species still persists, and Weismann does not deny such variability, nor even the inheritance of acquired characters in the Protozoa. (8) Maupas insists that Weismann should have experimented before he theorized, but
* Proc. Acad. Nat. Sci, Philad., 1889, pp. 70-5. + Ann. de Microgr., ii. (1889) pp. 168-72. + Biol. Centralbl., ix. (1889) pp. 14-23.
ZOOLOGY AND BOTANY, MICROSCOPY, ETO. 539
Gruber points out that even Maupas’ researches owe their impulse to the precedence of hypotheses.
Gruber notes two cases, one observed by Jickeli, the other by him- self, where the micronucleus of a Paramzxcium appeared to be absent, but where the symptoms of senile degeneration were not exhibited. According to Gruber the macronucleus consists of “ histogenetic” plasma, the micronucleus of germ-plasma.
Finally, Gruber refers to his recent experiments on Actinophrys sol. The marine form, with few vacuoles, soon acquires them in fresh water, which soaks in much more abundantly. The reverse experiment was also made. The marine Ameba crystalligera also became richly vacuo- lated in fresh water. None of the environmental variations, however, were more than transitory, that is to say, they disappeared when the original conditions were restored.
Two New Infusorians.*— M. Fabre-Domergue describes a new species of Colpoda, which he calls C. Henneguyi, which was found in an old maceration of leaves and dried detritus collected in the garden of the Collége de France. Its slow movements and its large size would make it comparatively easy to study, were its protoplasm not obscured by fine and numerous granulations. It differs in furm from C. cucullus, and normal individuals vary from 0°31 to 0°65 mm. in length. After describing the details of its appearance, the author states that it gives rise to division-cysts and to lasting cysts; the former have a very delicate membrane, and the contents divide into four. The lasting cysts are smaller and more rounded, and have a thick and resisting envelope.
Pronoctiluca pelagica is the name given to a new genus of flagellate Infusoria found on the surface of the sea at Concarneau. In the form of its mouth, and the presence of two flagella, it approaches Chilomonas, but, on the other hand, its tentacle is exactly like that of a Noctiluca minus the striation. The author believes that we have here a form which is intermediate between the Flagellata and the Cystvflagellata.
Anoplophrya aeolosomatis.;,—Mr. H. H. Anderson gives a descrip- tion of a new ciliate infusorian parasitic in the alimentary canal of Aeolosoma chlorostictum (Wood-Mason, MSS.). It differs from all members of its genus except A. mytili in possessing a single contrac- tile vesicle, and from it it may be distinguished by the shape and form of its endoplast, which is axial, band-shaped, extending nearly the whole length of the body, in most specimens straight, though in a few some- what curved or 8-shaped; this endoplast is coarsely granulated, and in one specimen, five large and highly refractive, though not crystalline, particles of different sizes were seen in it. The surface of the infusorian is densely ciliated, and finely striated in a longitudinal direction. The contractile vacuole is situated centrally above the endoplast. An inter- esting process of multiplication by transverse fission, was observed to resemble that which takes place in A. nodulata. It was noticed that the individuals in process of division were far larger than those that were not being divided, and that the segments were very much smaller than the parent one.
* Ann. de Microgr., ii. (1889) pp. 353-7 (1 pl.). + Journ. Asiat, Soc. Bengal, lvii. (1889) pp. 381-3 (1 pl.).
536 SUMMARY OF CURRENT RESEARCHES RELATING TO
Formation of Spores of Gregarine of Earthworm.*—Dr. F. Henneguy has applied the section-method to the study of Gregarines. The two chief difficulties met with are the small size of these creatures, and the resistance offered by their investment to the penetration of fixing liquids; these are best met by hardening the organisms in the organs which containthem. Observations have been made on Clepsidrina blattarum, Klossia helicina, and Monocystis agilis ; but the last alone has as yet given good results.
If a series of sections of the so-called testicles of the earthworm are made in May and June, almost all stages in the development of the parasite may be observed. The young consist of a small mass of homo- geneous protoplasm, which is surrounded by a delicate membrane, and contains a nucleus of some size, which is provided with a nucleolus which stains deeply with carmine. In the adult the protoplasm is filled with refractive bodies; these, when examined under a high power, are seen to be rounded or ellipsoidal in form, and they may or may not be of the same size. The author agrees with Maupas in regarding these bodies as being amylaceous. From the characters which they present with polarized light, it would seem that their axial portion consists of a substance which is more condensed than the rest.
The general results of previous observers on the development of Monocystis are confirmed, and some new facts have been discovered as to the part played by the nucleus. When a Gregarine is about to undergo encystation the nucleus has a large nucleolus, and the surrounding protoplasm is devoid of refractive bodies. Vacuoles soon appear in the nucleolus, and this breaks up into several small grains of chromatin which are connected by an achromatic plexus. The nucleus then under- goes indirect division, and what appears to be an accessory nucleus is developed. If the contents of the cyst do not divide, the nuclei continue to multiply by karyokinesis and emigrate to the surface, where each ~ nucleus is soon surrounded by a small quantity of protoplasm. At the moment when the peripheral layer of the cyst becomes organized into cells one does not see around each nucleus the radiating lines which are. observed in the parablast of mesoblastic eggs when the nuclei become the centres of cell-formation. It is very probable that the small size of the cells of the cysts of Monocystis alone prevent us from seeing those radiate lines which appear to play an important part in the formation of the cellular plate. Hach small superficial cell of the cyst soon becomes surrounded by a resistant envelope, and becomes a spore or pseudo- navicella.
Some of the nuclei remain at the centre