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Show 50 ON CIJASSIFICA'l'ION. is difficult to see with what these can correspond if not whh smne modification of the water-vascular system.* Fig. 23. c Fig. 2~.-The Echinorhynchus of the Flonnder.-A. Diagram exltibiting the relatirc position of the organs. a. Probo cis. b. Its stem. c. Antel'ior rnlal'gement. d. Body. e. Posterior "funnel." f. Neck. g. Meniscus. ft. Supel'ior oblique tubular bands. k. Inferior mn des of the proboscis. l, m. Genitalia. o. Penis, m· vulva. B. Lower extremity of the stem of the proboscis. a. Ganglion. b. Interspace. d. Outer coat. c. Inner wall. c. Tubt1lar band, with the nerve h. f. ~I uscular bands. g. Suspensorium of the genitalia. C. Pal't of the lcmnle grnitalin . a. Ovary. b b. Ducts leading from ovary to uterus (spermiducts ?). r. Open mouth of oviduct. d, e. Uterus and vagina. Leaving the division provisionally termed Scolecida in this confessedly unsatisfactory state, I pass on to tho ANNELIDA, 11 class of large extent, containing the leech, the earthworm, the S ·ipunculus, the lobworm, the seamouse and Polynoe (Fig. 24), the Serpula, and the Spirorbis. A.ll the members of this class possess a nervons system, which consists of a longitudinal series of ganglia, situated along one side of the body, and is traversed anteriorly by tbe oosophagus, the proo-oosophageal, or so-called " cerebral," ganglia *The recently published investigations of Leuckart. while they demonstrate still more clearly the close affinity which exists between the Acanthocephala and the T<Eniada-by proving the adult worm to arise by secondary growth within a hooked embryo, in the former case as in tho latter-leave some doubt upon tl1c natmr of the reticulated canals. According to Lcuclmrt, they arc tho remains of the cavity which primitively lies between the wall of the embryo anJ the contained rudiment of the adult Acn.nthocephalan body. THE ANNELIDA. 51 being connected by lat ral rmnmi sural corcl. with the po tcesophageal ganglia. In many of these animals the body is divided into o·m nts ac~ of which corre ponds with a sing I pair of gangliab of th .. ' cham, and each of these s gments may be provided with a pair of lateral appendages; but the appendages are nov r arti u]at d . and are. never so modified, a to be converted into ma, ticator ' organs, 1n the cephalic region of the body. · No Annelid ever pos ssos a heart comparabl to tho h art of a Oru. tacean, or In oct· but a system of ve s I w'th ' ~ ' 1 11101'(' or less xtensively contractile walls, containing a cl ar flnicl usually r d or ?Teen in ~olour, and, in some rare ens only: f'Orpus:ulat.ed, IS very . generally developed, and send prolongatiOns Into the respiratory organs, wher sneh exist. 'rhis has be n termed the "pseudo-hremal" sy tem ; and I hav Fig. 24-, ~L;~~:·: 4~ ·:.·jJ ~·;:~~-~qr 7 ·:.?Z.1 ~~<~,x ~~'+.[' /~ ~~3~· ~.{·.:.~~.~..- .'.~. ;}'?~ /r~ . . .Fig. 24.-Polynoe srpwmata . . \. VIewed from abo\'e and enlarged. a, b. Feelers. c, d. Cirri. e. Elytra j pace left B phetw.~e~ tl:e.tw? pos~erio~ elytra. g. Setre and flmbri re of the elytra.' · · ~stc111f0i1 . extlemJty, mfenor view, the ::~ppenda()'es of th r left side being omittetl. rt. n enot· tubercle. :::. , (;. · .ecti.on of hal r a somite with elyt1· 011 • · N t 1· 1 I) s f z. l o .opoc 1um. rt. Neuropodium . . · ect10n o half a somite with cirrus. |