40 
MOLLUSCA. 
Dokis*, ('/<?'. 
Have the anus open on the posterior part ot tlie back, the branchiee 
being arranged in a circle round it, under the form of a little tuft, the 
whole resembling a sort ot flower. The mouth is a small proboscis, 
situated under the anterior margin of the mantle, and furnished with 
two little conical tentacula. Two other claviform tentacula arise 
from the anterior superior part of the mantle. The openings of the 
genital organs are approximated under its right margin. 1 he sto- 
mach is membranous. A gland interlaced with the liver excretes a 
peculiar fluid through a hole near the anus. The species are nu- 
merous, and some of them large. They are found in every sea, 
where their ova, resembling gelatinous bands, are diffused over 
stones, sea-weed, &c.f The 
Onchidora, Blainv, 
Only differ from Doris in the separation of the genital organs, the 
orifice of which communicates by a furrow running along the right 
side as in Onchidium.]; In the 
Plocamoceros, Leuck. 
Have all the characters of the Onchidorse, in addition to which the 
anterior margin of their mantle is ornamented with numerous branched 
tentacula ||. 
PoLYCERA, Cal'. 
H ave the branchia;, as iii Doris, on the hind part of the body, but 
more simple, and followed by two membranous laminae, which cover 
them in moments of danger ; anterior to the claviform tentacula. 
* A name firit applied by Linnrcm to an animal of this genus, which, however, he 
characterized badly. It was afterwards extended by Muller and Gmelin to almost 
the whole of the Nudibranchiata, and restored by me to its original signification. 
-f- Species with an oval mantle projecting beyond the foot: Boris verrucosa, L., 
Cuv., Ann. du Mus., IV, Ixxiii, 4, 5 : — Doris argo, L., Eohatsch, Anim. Mar. V, 
4, 5 ; — Boris ohvelata, !Miill., Zool. Dan., XLVIII, 1, 2 ; — Doris fusca — , Id., Ib., 
LXVII, 6, 9 ; — Doris sfellafa, Bomme, Act. Fless., 1, iii, 4 ; Doris pilosa, Mull., loc. 
cit. LXXXV, 5 — 8 ; — D. leevis, Id., Ib., XLVII, .3 — 5 ; — D. muricata, Id., LXXXV, 
2 — 4; — D. fubercidata, Cuv., Ann. du Mus., IV, Ixxiv, 5 ; — D. limbata, Ib., Id., 3 ; 
— D. solea, Id., Ib., 1, 2 ; — D. scabru, Id., Ib., p. 44 6 ; — D. macxdosa. Id., Ib., — D. 
tomenfosa, Id., Ib. D. nodosa, Montag., Lin. Trans., IX, vii, 2 ; — D. marginata, 
Lin., Trans., VII, vii, p. 84 \—D. nigricans, Otto., Nov. Act. Nat. Cur., XIII, part 
II, pi. xxvi. f. 1 ; — D. gramdiflora. Id., Ib., XXVII, f. 3 ; — D. ligrinu, Sav. Egyp., 
Gasterop., pi. i. p. 3 ; — D. concent risca, Ib., f. 5 ; — D. niarmorata, Ib., f. 6, &c. 
Prismatic species, where the mantle is almost as naiTOw as the foot : Doris laccra, 
Cuv., Ann. du Mus., IV, Ixxiii, f. 1 and 2; — D, atromargina.ta, Id., Ib., Ixxiv, 6; 
D. pustidosa. Id., Ib., p. 473 ; — D. gracilis, Rapp., Nov. Act. Nat. Cur. XIII, part 
II, pi. xxvii, f. 10. See also Van Hassel. Bullet. T"niv., 1824, Octob., Zool., p. 
235. 
t Onchidora Leachii, Blainv., Malac., pi. xlvi, f. 8. 
II Plocamoceros ocellatus, Leuck., App. Ruppel., Invert, pi. 5, f. 3. 
