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Show 152 ON NEW SPECIES OF EARTHWORMS. [Feb. 16, body-wall; lg'., their distribution to the wall of the buccal cavity; ne.o., the aperture of the first nephridium ; neph'., the first nephri-dium; ov., ovary; ov.f., oviducal funnel; ov.p., oviducal pore; as., oesophagus: Phar., pharynx ; pro., prostomium ; prost., prostate ; sal.g., salivary glands; sp.d., sperm-duct; sp.p., male pore; sp.sac, sperm-sac; spth., spermatheca; spth.p., spermathecal pore; T., testis; vis.n., visceral nerve, from brain to wall of buccal cavity and pharynx ; x, ciliated cells on roof of pharynx. Fig. 4. Transverse section through Plutellus. 1, 2, 3, 4, the positions occupied by the four chaetae on each side ; ep., epidermis, represented as a black line ; cer., circular muscles of body-wall; lg., longitudinal muscles, which form a thinner layer dorsally than ventrally; D.v., dorsal vessel lying partially surrounded by a " perihaemal cavity" (p.h.sp.); N. C, nerve-cord; n'., ventral nerve; n" ;, ventro-lateral nerve; neph., portions of the loops of a nephridium ; neph.d., nephridial duct, opening at ne.o.; perit.gl., a "peritoneal gland"; sept., septum; v.v., ventral vessel. 5. Ventral surface of Microchceta papillata (nat. size), c.p., c.p'., the copulatory papillae (suckers) on somites x. and xxiii.; m., mouth; Pro., prostomium ; t.p., ridge at each side of clitellar region, probably representing tubercula pubertatis. The roman numerals indicate the somites, some of which are biannulated (a, b). 6. Side view of M. belli, in order to show the deeply marked annulationof the somites, a, b, c, the three annuli into which the surface of the somite is divided. The roman numerals indicate the somites. Buc, the protruded buccal cavity; ne.o., nephridiopore; l.ch., the outer couple of chaetae ; v.ch., the inner couple of chaetae. 7. The copulatory papilla of somite x. of M. papillata. Pap., the papilla ; pap'., the small papilla in the apical cup, showing the pore of the internal organ as a small dot; V.ch., the ventral chaetae of somite xi.; v.mid., the ventral midline. 8. Side view of anterior end of M. beddardi, in order to show the fusion of somites i. and ii., referred to in the text, prost., prostomium ; neo'., first nephridiopore. 9. The " sucker " or internal organ, corresponding to the external papilla of somite xxiii. of M. papillata. s.s'., the septa of the segment; m., the muscle of the chaetophore. 10. A somewhat diagrammatic view of a transverse section of the " sucking-organ " (combined from a series of sections). Ch., the chaetae surrounded by the apparatus; circ, circular muscles of the body-wall, continued over the "sucker"; el., clitellum ; co.ep., coelomic epithelium covering the organ ; ep., the epithelium lining the " sucker "; gl. the gland-cells of the organ ; lg., longitudinal muscles of the body-wall; m.ch., the muscles of the chaetophore ; mus., the muscles surrounding the " sucker "; pap., the external papilla; pap'., the smaller papilla contained in the apical cup of the larger ; pore, the pore of the apparatus. 11. A portion of the wall of the sucker of M. papillata ; only a small portion is filled in in detail, co.ep., the coelomic epithelium, dipping down between the groups of gland-cells (gl.); b.v., blood-vessels; ep., epithe lium of the organ; mus., muscles in various directions in the wall; ner., nerves cut across. 12. The tip of an ordinary chseta of M. belli. 13. The sperm-sacs of M. papillata. A, B, the chief sacs; C, D, the smaller posterior lobes of these. A, B have been opened on the right side, showing the contained ciliated rosettes (cr.) and testes (t.): cat., calciferous gland ; giz., gizzard ; sep., the strong septa. 14. A transverse section of the tuberculum pubertatis of M. belli (only a portion is filled in with detail), cp., epidermis of clitellum ; circ, circular muscles bcleololsd- ovfe stsheels t.u boefr tchuel ubmo dpya-swsa liln,w baertdwse;e nl gt.h,e fliobnrgeistu odfi wnhali cmhu sthcel egsl-a ndb-.v., |
