Ihi^ lininchlcl i' 



, „ i-„„ „i„(„= I hive met «Ull an accident which has ilisnhlcil my right arm nml inuvcnU-.I mt L-\cciiliiig ihi- drawi 



Since cxeciUing ihi.- drawing* fur Ihc prtccdmg i)lales, I liJ^e met «mi .m :ii.li.ie" j t, 



for this plalir with so mitch exactitude as I desired. 



IT-- I W „,„„, Ttl- r/rU, AA Uc 1 Cam.-Iuc.1 Transverse section through the middle of the body: the section has i.assed thrniiell the third parapodilim and 

 Fig. \. M.ffitfat,,Lth. ('^""'>7- ':^;''. ^^ &.C Ventral nerve-cord, /cm., icw. Longitudinal commissures. Hit.. Sl.i.nnch. (;h. Iii- 



vesicula seminal.* on one s.de. and htough a «Emenlal £*,i"'""^^Xi. to iL "ctuderm of the dorsum. OV.. OV. Ova. dv. Dorso-vcntral muscles, mx. Musculus-cnlrnlis. i>.l. Musa.l... 

 tcstinal branches. '^ ^■l?:^^^'-''^'^*^"'^^^ ganglion. «. The fibr.llar prolongation passing from the ganglion imo .he pura,o.l,um 



protractor lung,.s. ^ ^^-^^ook^ J^^'^S " % (Zeiss F ol. V Arbitfary ma'g.iificafionO Transverse section (fiff. ^) and horizontal section 0'!f-^^"->f .h. neurilvmi 

 sheath of the dorsal s!dc of the ^cnlraliiervc-cord, showing the peculiar structure (vide pp. 27 and 72l- In fig. 2, this structure .s only present m the muldle, whdst the portions 

 of'fhe sheath, at both ends of the ^'g"'"- Ji;- "'j*' ."^^ schematically, the two dilTcrcnt types of ganglionie cells and nervous lubes (vide pp. 30. 34 



, -ru n" -.h r\',','ntVnAiion formini; directly, a nervous tube are indicated by the letter C, and the cells with a prolongation which becomes loosened out i 



and 74, 75)- ^he .-dls w,th '^ 1' «'""E-" "'' /" " " E' ^;.',^"'.^> _^^„^ ^^^.f,„,,, ,^ „, ^g^ ,9 ,„d ^2,. ,.. Smalk-r cells situated in the middle of the cord, their prolo „ 



the t,).n)lar ret.cnIa..on ^/"f ,^f;\?> 'V'^^j'^'^^/l^, ^; p,„,„„„^^ .brough the commissures, into a peripheric nerve of the same side. c.\ Cells, situated at the margin .>f 



at.ons forming -^hmsmn '■ ■■"' ^ ;,roloc" "on! through a transverse commissure, into a peripheric nerve of the opposite side of the ventral eor.l. r.". Cells, situate.l at the rout 

 ,he ventral cord, wh ch *^""\ J.''^^'^ ' .^^^^^^ „.e nerve, c".-. A multipolar ceil in similar situation to ,:". r\ Canglionic cells, whose prolongations become loosened 



'''rr^^lM^Mi^o^^"^W^^ -tuatcd on same side as they themselves ..re. r.K CeUs, whose prolongations become loosened ou, into the fibrillar 



out m. > '''\fJ'[ 7,, , S s" e r.\ Cell whose proIoURation passes to the longitudinal nervous tubes (l.t ) of the oppos.tc longiludmnl commissures. 1. :Nervous tubes origmatmg 

 reticulation ot ""■ ' 1'"' \ , . |^,,„i,,..,;„„i commissure of the same side. 2, Nervous tubes originating in the fibriU.ir reticulation of the opposite longitudmal commissure. 

 '" M ^X. o iJfnl"nc ii he Eri^ "mnis lubes (U) of the longitudinal commissure of the same side. 4. Nervous t,d>es originating in the longitudinal tubes .T U, 



opiSrioiigiiriinal e^^^^ U. lUindle of louEiludinal nervous tubes running along the inner dorsal side of each longitudinal commissure. /./.'. Smaller bundle of longitu,!,,, 



nervous tulies ruuniiig almig Ue "^'^^'j^J"^^^^," ^^'''^^^ "El',"trausverse section of the ventral nerve-cord, illuslr.iling the two different types of ganglionic cells and nervous IuIk-, .u 

 ^ ■ rh, -«.«L- of the" cell 'nrohincations. The section h.is passed, on one side, through the root of a large nerve {n. »(.) : in the middle, it has passed along one side of a !.n- 

 SL7 efs omZsu e nuron' the ^^o^ i. ha. passed 'between two nerves, As in fig. 3. the cells whose prolong.itions. directly, form a nervou. tube arc indicated bv ,i, 



SrTand r Veils whose prolongation- bee<.me loosened out into the fibrillar reticulation are indicated by the letter r. rhc nervous tubes are indicated by numeral. r.'. Me,. , 

 ells I'co esnonS lo e', lig. 3) «hose prolongations traverse each other, and pass through the longitudinal commissure int., peripheric nerve- on each side. r.\ Cells situated ... 

 «r uos fcorre, londinc l- '■ ^ and r • in fig, 3.. c.\ Crout-s of cells 1 corresponding to r,' in fig, s'l whose prolongations pass, through tlie lransver>e commissure, int.. nerves of the oppos.tc 

 sidr <■ ' I Irou.s of eells sending their prolongatio.is di.ectlv into the nerve at the root of which they are situated. <■.', Isolatc<l eel! thai sends ,ts pr.dongal...n, thn.UKh the transverse connmsMire. 

 IntVthe'lni nerve of the opposite side, ,■. '. 1 nrge cells whose prolongations become, immediately, loosened out into the fibrillar reticulation, ..', Cells. « itli spre.ding rct.culrted ptMnngn.,., 

 1 tua d bX«^hc "xlremities of the transverse commissure, and pertaining to the same group rf cells as c."-. ;■.'. Small cells, with reticulated prolongations, situated un the inferior side of of tl 

 fonintudimil commissure r * Cell whose prolongation passes, a short distance, into the fibrillar mass previous to becoming loosened nut vide fig. 6 d), r.*. Small cells, situaleil under the root 

 ihhfec nerve lvidcliE"6a) C " and r' Small cells situated in the fibrillar mass; n' has two reticulated proloug.itions Ivide also fig. 6 b\ r.' is multipolar l.vide fig. 6 c\ 1. Roots of nerv.. 

 tubes', corresponding l"'those indicated by same numeral in fig. 3. 2. Roots of ner.ous tubes (corresponding to numeral 3 in fig- 3^ originating amongst the longitudinal nervous lubes of U.e , 

 «Mfntudinal commissure of the same side. 3. Root of nervous lubes, corresponding to numeral 2 in fig. 5. U Frans-sectcd bun Iks of Ion,, tudinal nervous nd.cs of I'.e long.lu.lmal , 

 commissure ti.t Itundle of nervous lulics passing lo a peripheric nerve. (.71. Intermediate nerve, from which a branchlet passes i j . nt of the lon„ ludiml e mmissutes. 1 he hbriK ■■' 

 ■ one from each lube •>( the intermediate nerve (vide also fig. 14 iu which a similar branchlet is illustraled), n.sk (tuter ncunkmiii shcith * nsf Inner neurilemma-shen 

 Fie. 5. .1/ iiiytiutiitm, ». sp. Ideal ir.insverse section of ihe ventrel nerve-cord, passing through thi. rools of luo of the large ner\cs, and through ., 

 thin transverse commissure where k p.iir of large ganglionic cells is situated. The litera-siguifications are the same as iu tig % Some cells e ^ t ^ which nrt connecte.l witb 1 

 thick transverse commissures, are also iUuslrated in this figure, C. I'air of large cells corresponding to c' in fig- 3: the prolongations or Ihest cells ire seen to be m coiumuuu:iii 

 with the fibrillar mass of the longitudinal commissure by means of small lateral branchlets, as shown in fig- 6 f. c.'\ Multipolar cell situated it the root of a nerve .and, sending 

 prolonuation directly, into the nerve, r.-. t:ells with spreading reliculatcii prolongations, situated among the cells indicated it e in hg 4 ' " tells whose prolongations bcL-.i 

 loosened out among the longitudinal nervous lubes, 4 Koot* of nervous tubes origiur.ting in tlie fibrillar reiiculation on Ihe eMcri r I rsnl ^ dc of the longitudinal commissure; i.i. 

 of the tubes, emanating from the reticulalion, ate seen to originate in the ventral part of the fibrillar mass of the longitudinal commissure (l). 



Fie. 6. Jl/. ijignutcnm, n. up. (Zeiss F- Oc. I- Cam.-luc. Ror.ix-c.irmine, Picric acid). DilTerent forms of gauglionic cells, with spreading rcticulal 

 prolongalioiis, illustrated from transverse sections, h. and C. Unipolar and multipolar cells, situated in the fibrillar mass of a longittldiual commissure. rf. Cell with prolongmior. 

 which, for a consiik-r.ibU- distance, remains individcd. 



Fig. 6 e. (/ciss l'. l)c. 1. Cain.-lue.' Large ganglionic cell with reticulated prolongation, corresponding lo c.' in fig. 4, and lo PI. V. hg, 9 d. am, fig, 12 nc-. 



Fig. 6 f. ., arbitrary mogiiificntion.) (i.ingbunic cell whose prulungation. .lireclly, forms a nervous tube. In ihis figure. I>ranch!ets (<jr.) issuing from ihc prolongation 



ure indicHlcil, 1 ihink ihnl these bring the prolong.ilion inlo uonmumicalion with the fibrillar reticulation, and that the nervi.us tubes ate, thus, brought into cmmunication Willi each oiher- 



Fig. 6 g. M. ynif/i, 11. sp. (Zeiss horn, im. '/,«. (Jc. !.■) Canglionic cell from the ventral side of a longiiuilinal commmissure. The cell has one probiugation. 



whid) forms, directly, a nervous tube, but there is. however, another prolongnliou (h). which appears as if it issiic<l from the nucleus. I (|iieslion this, however, Aiul in sjiiu- of the 



most minute examination with a Zeiss '/,«, could arrive at no certain dclermination. 



Fie. 7. M. graf'li, n. ap. (Zeiss V. Oc. i. Cam.-luc.l Longitudinal section of n large neric, close to its root (portion of n transverse section of the boily', 

 showing ganglionic cells [>ir.. iir.') siiu.itod within the fibrillar mass c-f the nerve. It appears as if the two cells were united at k; Iberc is a protoplasmic thickening at ihis s|p,,i 

 it., i'." Ic."'. Conne:tive-tissue nuclei situated jii, or at, the sides of the fibrillar mass. k.'. Couucctive-tissue nuclei, situated in the reticular connective-tissue (6.) surronnding lie 

 nerve, and having communication with the ncurilemma-shcaih \n.s/;.). 



Fig. 8. (Zeiss horn, im. '/i-- ^^'^- '■) Secliou of ganglionic cells, with nuclei in different Stages of division (direct division?), a., a'., 0. Cells of die 

 nentr-il ncrvc-cotd of M. t/rii/'/l, «. «p. e. Cell of the fibrillur mass of the oesophageal-ring of M. gtgantcum, n. sp. In this cell, distinct indications of a cellular scfimcntatinh, 

 similar to that of a leucoeyt, are seen. 



Fig. 9. M. ijraffi, n. ap. (Zeiss liom. im. '/ib- Cam.-luc.) Ganglionic cells of the ventral nerve-cord which have, I think, just undergone division; Ihc prolong- 

 ations are, ns yel, still united. 



Fig. 10. M, griiffi, n. ap. (Zeiss F. Oc. 2. Cnm.-luc. Borax-carmine, I'icric acid.) Transverse section of a nerve (root of the 6th pair of fine nerves, \i<li 

 PI. v., fig. 3, H".) showing the cylindrical structure of the nervous lubes; the latter vary, considerably, in thickness. Connective-tissue nuclei are seen, situated in Ihc inner neurilenmi.i. 

 sheath. The outer neurilcmma-shealh is very thick. 



Fig. II. M. gujantinim, n. ap. [Zeiss F. Oc. 2. Cam.-luc.) Section of a nerve, which, in the bulk of the figure, passes along the nervous lubes but at itu 

 end of Ihc figure Iranssecl* Ihcm obliquely, owing lo o curving of the nerve; the cylindrical structure of the nerve, thus, becomes apparent, and the dark coloured fibrils are seen !■• 

 be. the septa of spongioplosm which enclosing the nervous tubes. 



Fig. 12. (Arbitrary maguificalion."i Two portions of nervous tubes traversing one of the longitudinal commissures, and issuing from ganglionic cells; showing 

 Ihc slight tumefaction of the lubes at the point where branchlets are given off to Ihc fibrill.ir reticulation. 



Fig. 13. M. giijaiitntm, n. sp. (Arbitr.iry nmgnificnlit.n.) Portion of horii^ontal section of a longitudinal commissure at the point where a large nerve is given 

 off, illustrnting, schematically, the different types ot nervous tubes received by a nerve from the ventral cord, i. Nervous tubes passing through the large itansvetse commissures 

 nod cinanaling from ganglionic cells, or the fibrillar reticulation of the opposite side, 2. Tubes origioating in the bundle of longitudinal nervous lulics {It.) running along Ihe inner 

 side of the longitudm.il commissure, 3. Tubes origioaliiig iu ihe fibrillar reticulalion. 4, Tubes originating in the smaller bundle of longitudinal nervous lubes [I.IW ruiiuiui; 

 along ihe outer side of tlie longitudinal commissure, (■'. Ganglionic cells which send their prolongations, through the longitudinal commissure, into the nerve. < ■■". Ganglionic c 

 cone, ponding lo those mdicalcd by <"' in fig. 3. v^. Cell with spreading reticulated prolong.-ition. nsk. Neurilemma-shealh. 



Fig. 14. M. giyaiiUitm, 11. up. l/ciss F. Oc. i. Cnm.-luc,| Transverse section of an intermediate nerve, at a point where a brnuchlct is given off. 

 br.inehk-l i^ seen to consist of small lubes issuing, one from each of the few thick longitudinal nervous tubes of which the intermediate nerve is composed. 

 Fig. 16. M, !/rii/'fi, II. «/', l.Zeiss hom, im. '/,.. Oc. 2 Cam-Iuc.) Connective-tissue nuclei. 

 Fig. 16. M. glabritm, l'\ S. L. '.Arbitrary magnification,! Secliou of the striate, ciliated cuticle covering the glandiilous tissue of a .segmental glnndulous sack. 

 .■\i uniform intervals, broader, non-suialc spaces (a, I occur (probably secretive porcs.^l. The roots, alone, of the cilia arc seen. 



Fig. I7. jV, grafl'i. u. up. (Arbitrary inngnific.ition.l Ideal, horiionlal section, illustrnting the alimentary canal, and tanification of Ihc intestinal br.iiiches 

 (tg'.. tg'., tg'.). The cloneol canal is considerably shortened in the figure (vide fig. 20% a. Annular epithelial protuberance dcmnrcaling the oesophagus from the slomaeh. 

 (I.e. Annular conslnclion. dividing the stomach into anterior an<l posterior divisions. The constriction is, here, much dr.-iwn back and the division, consei]uenlly. is nut very dislinC 

 h. /i'. Septa separating Ihe intestinal branches, c. Annular con>lrietn)n separating the stomach from the cloacal canal, orrf. l.alcto-ventral oviducts opening into the cloae;il cann 

 an- Cloacal aperture, tr. TeuiacidaT nerve-ring. or. Oesophageal ring, ».C, Ganglionic cells situated, annularly, around the oesophagus, at the posterior extremity of Ihe probo%ei 

 ri.c*. Ganglionic cells surrounding the lenlaculnr nerve-ring. 



Fig. 18. M. cnrprntL-ri. Ideal, horizontal section simitar to that in flg. 17. The litera-siguifications are the same as in fig. 17. The oesophagus (ttJt.l is, here, 

 prelly long and surrounded by muscles and ganglionic cells. The subdividing of the stomach is verj' distinct; its anterior part is subdivided by a small annular conslriclion (dl. 



Fig. 19. M. yigtis, jAk. Ideal, horizontal section similar to those of ihe two preceding figures. The litern-signlfications are the same as in figs. 17 and iS. 

 In this species, and, also, in M. giganteum, two pairs, only, of intestinal branches (tg.', tg.-) issue from the stomach. The subdivision of the sloniaeh is dislincl. eg. Large gtoiip' 

 of ganglionic cells surrounding the oesophagcal-ring \,or.). The cerebral ganglia are. in this species, largely developed. 



Fig. 20. M. grafl'i, n. ap. (Zeiss AA. t)c. 1. Cam.-luc) Longitudinal section through the middle of Ihc body, showing the situations of the alimentary canal, 

 the nervous system, ami the oviducts. The course of a lateral oviduct is shown in Ihe figure, in order to illustrate its situation in relation to the nervous system and alimentary 

 canal, althrough it, of course, is really, siluated more laterally. WM. Mouth. Ol'. Annular constriclion separating the oesophagus from the stomach, a.c. vVnnuIar constriction subdividing 

 the st,iinnch, d. Annular constriction, through which there is only a very narrow passage inlo the cloacal canal, an. Cloacal aperture. Ovd. Dorsal oviduct, (i. Origin of later"- 

 ventral oviduct. otid", ovd'. Latcro-vcntral oviduct, b. Opening of the oviduct into the cloacal aperture, or. Ova. c. Portion of the body-cavity, in which ova arc situated- 

 b.H. Ventral nerve-cord. trm. Thick transverse commissure al the anterior extremity, and few.' the similar commissure at the posterior exircmity of the ventral nerve-cord. O.ri/i. Uoi " 

 of oesophageal commissuies, n. Otii pair of fine nerves, or. Oesophageal ring. {r. Tentnculnr nerve-ring, m.b. Muscular bulb. 



Fig. 20 a. (Zeiss AA. Oc. 1. Cam.-luc.) Portion of a longiiuilinal section, of the same animal, as in fig. 20, but passing somewhat more laterally, and illustrating 

 the course of a latero-venlral oviduct, Ovd. I'orlion of the dorsal oviduct (ulcrui). oPrf,', ovd.-, ovd.'. Latero-ventral oviduct in which ova arc silustcd. n.c. corresponds lo «,f. in 

 fig. 20. m.h. Muscular bulb, Im. Intestinal branch, (i. Nerves, r.rf. Vas deferens, p.^, p.". Third and fourth parapodin. h. Chief hook. S.h. Supporting rod. in. Musclc> 

 converging in Ihe parapodin. 



Fig. 21. M. giganteum, n, sp. (Zeiss AA. Oc. 4. Cam-Iuc.) Transverse section of the ahmeutar>' canal, at the demarcation of the stomach and the cluneal 

 cunal. m.e. Portion of the epithelium of the stomach, nt. Annular muscles surrounding the stomach. r.m. Radial muscles, M'. Small muscles situated in the walls of the cloacal 

 caoal. am. Opening of the Intcto-venlral oviducts inlo the cloacal canal. Ovd'. Dorsal oviducts, or. Ova in the cloacal canal, c. High cpilhelium on the ventral side of the 

 tloneal conal; it is seen to be much flattened ou tne dorsal side of the anterior part. v. Ventral ectoderm. 



Fig. 22. M. giganti'Uin, n. sp. (Zeiss F. Oc. i. Cam.-luc.) Transverse section of epithelium (me.), and the wall of the stomach, in which arc situated annular 

 muscles (m.) and small radial muscles (.rm). a. Cells which send a prolengation low.irds the annular muscles or the epithelium (possibly nerve cells?)- 



f 'B- 23. M caipiiiUri, Grnff. (.\rbitrary mugnificnlion.) Ideal, horizontal section, showing the situation of ihe oviducts, and the form of the uterus and ihc 

 ovarium. Three pairs of branches, filled with ova. issue from the uterus, and. along the walU of these branches, minute ova are seen lo be situatc<l covering the walls as an eititheliu 

 rf. Dissepiments, separating the branches of the ovarium or body-cavity, in the dissepiments iransscctcd bundles of muscles arc seen. rf.". Indications of «mall dissepiments, a. C', 

 nectivc-tissuc situated over the anterior part of the alimentary canal and the proboscis, oi?d. Dorsal oviduct, ovd:. Origin of lalero-vcutral ..viducts. 



. . , ., ^^',.?L L "■ '^'"■'/'■^'""' ^- *■ ■'■'■ LZciss F. Oc. I. Cttm.-luc.) Section of ova in process of segmentation, situated in Ihe cloacal canal. I have, frequently, 



obsened simdar ova. Whether (his segmentation begins without a prior fertilisation, as Graff supposes. I am unable to :.ay. I am. however, more inclined to think that they 

 fertilised by occasional spermntoion passing through the cloacal apcrlure, into the cloaca! canal, along with the water 



