Fip;. I. M. giganteum, n. sp. (From photo, taken with a Zeiss AA.) Transverse section through the middle of the 

 body. The section has passed through the third pair of parapodia and the penis (f). h.s. The ventral nerve-cord. 

 mv. The stomach, with its ciliated epithelium, ov.d. One ot thi' latero-ventral oviducts, s.h. A piece of the sup- 

 porting rod. r.h. A reserve-hook. h.k. The liranch issumg from the hook-gland towards the centre of the 

 bod}-. In the penis ( t), the ductus ejaculatorius issuing from the vesicula seminalis is seen. 

 » 2. M. giganfemii, n. sp. Dwart-male. (iM'om photo, taken with a Zeiss CC.) Transverse section through the 

 anterior bod}-. The posterior part of the proboscis is transsected. Surrounding the proboscis, groups of ganglionic 

 cells (gr.),- pertaining to the oesophageal ring are seen. or. A small piece of the oesophageal ring. n. Branches 

 of the first pair of large nerves, t, t, t. Testes, distributed through the whole of the body. m.v.i. Musculi retract- 

 ores interni. f.g. A part of one of the parapodial ganglia. *■/;. Upper extremit}- of the supporting rod. rh A 

 reserve-hook. h. A piece of the chief-hook. 

 » 3. M. graffi, n. sp. (From photo, taken with a Zeiss AA.) Transverse section through the bod>-, at the point where 

 the 4th pair of parapodia is situated. m.v.k. The glandulous mass surrounding the stomach, ov.d'. The dorsal 

 o\iduct. ov.d. Latero-ventral oviduct. «., n. The 5th pair of large, and Cth pair of fine nerves, dv. Dorso-ventral 

 muscles, mc. Musculus centralis, f.g. Parapodial ganglion, p.f. Annular protuberance at the base of the retracted 

 parapodium. t. Testes. 

 » 4. 31. graffi. n. sp. (Zeiss AA. Oc. 1. Cam.-luc.) Transverse section through the anterior part of the bod>-. 0. r 

 Dorsal part of the oesophageal ring, surrounding the proboscis, n., n. Transsected nerves, f.g. Parapodial "antrlion 

 of the second parapodium. r.lt. Portion of reserve-hook. /;. Piece of chief hook. tm. Transsected intestinal branches 

 Ol', Ova. 

 » 5. M. cirriferum, F. S. Leuck. (From photo, taken with a Zeiss CC.) Transverse section through the posterior part 

 of the body ; the 4th pair of parapodia is transsected. The testes {t, t., t.) are seen extending to the ectoderm of 

 the dorsum and to the margin of the bod)-, ov.d. One of the ventro-lateral oviducts, ni.v. Stomach, fni. Inte- 

 stinal branches. 

 » 6. M. carpenteri, Graff. (Zeiss AA. Oc. i. Cam.-luc.)Transverse section through the middle of the body. b.s. The 

 ventral nerve-cord. s.o. A segmental glandulous sack. sph. Sphincter ot the aperture, ov.d. Latero-ventral oviduct 

 ov.r. Problematic organs — rudimentary ovaries presumabl}- — situated in branches of the uterus, d. Septum sub 

 dividing the uterus, d. v. Dorso-ventral muscles, dr. The dorsal ridges. 

 » 7. M. graffi, n. sp. (Zeiss AA. Oc. i. Cam.-luc.) Transverse section of a specimen with degenerated ventral nerve- 

 cord [h.s.). and capacious stomach {mv.) from which lateral branches issue. 

 » 8. M. carpenteri, Graff. (Zeiss AA. Oc. i. Cam.-luc.) Transverse section through the posterior extremit)- of the 

 body. cl. Cloacal canal, an. Cloacal aperture, f.e. Ciliated epithelium, ovd. Dorsal oviduct-aperture openincr into 

 the cloacal aperture, tm. Intestinal branches. '^ 



» 9. M. carpenteri, Grrff. (Zeiss CC. Oc. 2. Cam.-luc.) The cloacal aperture. The leitra-significations have the same 



application as in fig. 8. /. The tongued labiæ of the aperture. 

 » 10. M. gigantcnm, n. sp. (Zeiss AA. Oc. 5.) The figure illustrates the distribution of the sinistral nerve of the first pair of 

 large nerves (dorsal aspect), and is constructed from a series of horizontal sections; partly, drawn under the 

 Camera lucida, n. The fine nerve situated between the first and second large nerves; it anastomozes with the 

 posterior branch of the first large nerve. n.\ Mesial branch of the nerve ramifying into two branchlets, one pas- 

 sing to the muscles {m.) situated under, and between, the branches of the large nerve'; the other crossing the anterior 

 nerve-branches; it passes, presumably, to the muscles m.'. n.^ A branch ramifying into 3 branchlets, one of which passes 

 to be posterior parapodial ganglion [f.g.), a second branchlet [n.^) passes to^he muscles m.^. I have not exam- 

 imed the course of the third branchlet, but it is directed towards the hooks, g.n. Nerve running to the anterior 

 parapodial ganglion, d. The first portion of nerve (parapodial branch) running to the hooks and their muscles (the 

 distribution is shown in fig. 1 1). The anterior and posterior branches (cirri-branches), are, the large branches passing 

 to the margin of the bod)-, where the)- communicate with the epidermic cells (6.). They form, at each cirrus, a 

 complex ramification. In their course, the)- give oft" nerves («.*, n.^, n.^), to muscular bundles principall)- (for 

 instance, n.^ to m.'^). h.k. The inner branch, issuing inwards from the hook-gland, h. Supporting rod. s. /». 'Chief 

 hook. r. Ji. Reserve-hook. tm. Intestinal branch, c. Transsected depression in the ventrum, at "the external side of 

 the parapodium. 

 » II. M. giganteum, n. sp. (Zeiss CC. Oc. 4. Cam.-luc.) Distribution of the branch d of fig. 10. This branch is some- 

 what more dorsally situated than the branches illustrated in fig. 10. The branch ramifies into 3 branchlets (w.', «.2 

 W.3), «.' and n.', are principally distributed in the muscular bundles {m',ni.-,m\) of the hook-apparatus, vide i, 2, 3,' 

 4, 5, 6 etc.; some branchlets («.", and n'") pass to the walls of the canal however, encompassing the support'inc^ 

 rod (/«.), and pass onwards to the glandular mass (a.) in which the reserve hooks (r.h.) are situated. I have not exanv 

 ined the distribution of n.\ n.* is the same nerve as w.» in fig. 10. f.g. A few cells of the anterior parapodial 

 ganglion, b. A portion of the hook-gland, h. k. A small portion of the same glandulous branch as /(, k. in fig. 10. 

 » 12. 31. graffi; n. sp. (Zeiss AA. Oc. I. Constructed froin a series of sections and, partly, drawn under Cam.-luc.) Transverse 

 section through the mesial part of the bod)-, showing the distribution of one of the fine nerves, b.s. \'entral nerve-cord. The 

 nerve ramifies at its root into two branches (2, 3). From the ventral one, of these, several branchlets (i), immediately, 

 issue and pass to the ventral muscles. In the further course of the same ventral branch (2), the branchlets n.', n^ 

 and n:\ issue towards the ventral side, to muscles as well as, also, to the ectoderm ; n.* runs, probabl)-, to the musculi 

 retractores interni {m. r.); n.^ runs to dorso-ventral muscles; 4 passes towards the dorsal side. The dorsal branch, 

 3, ramifies into two branchlets running to dorso-ventral muscles, f. The inner outline of the parapodium. 

 » 13. 31. giganteum, n. sp. (Seibert hom. im '/g Zeiss Oc. i. Cam.-luc.) From a transverse section, showing the vertical 

 distribution of the nerve terminating in a cirrus, a., a. Nervous fibres passing to the epidermic cells, b. Anas- 

 tomozations of the nerve-branches. Nuclei occur, only sparingl)-, at the extremity of the cirrus. 

 » 14. 31. graffi, w sp. (Zeiss F. Oc. i. Cam.-luc. Borax-carmine. Picric acid.) Transverse section through the first 

 portion of a nerve of the first pair of large nerves, n. The second one of the 6 fine nerves, and situated behind 

 the first large ner\'e. The connective-tissue septa which form »den gefacherten Bau'< of the nerves, as described 

 by Hermann, is well seen in this section. Connective-tissue nuclei occur in the thickest septa. 

 » 15. M. graffi, n. sp. (From a photo taken with a Zeiss CC.) Transverse section through the mesial part, where one of 

 the proble matic organs, [ovr.), — rudimentary ovaries presumably — is situated, a. Bodv-cavitv, on whose dorsal side 

 ova are situated, i. Testes. o?;d. Latero-ventral oviducts, i.s. Ventral nerve-cord. «. Transsected' nerve, wi;. Stomach. 



