MOLLUSCA. 783 
sound which this little animal produces under water, Grant Ann. des Sc. 
nat. VIII. pp. 111, 112, and 8. Rem Ann. of Nat. Hist. xvi. p. 389. 
b) With branchice disposed in a continuous series; with cup of tentacles 
entire. 
Tritonia Aw. and Hane. 
Sp. Tritonia Hombergit Cuv. Ann. du Mus. 1. pp. 418—498, Pl. 31, 32, Moll., 
Mém. 4; Buarny. Pl. 46, figs. 6, &c. 
Polycera Cuv. Body attenuate posteriorly with belly flat, 
covered by a loose membrane. Dorsal branchiz in little branches 
or plumose, covered with membranous lamine or papille. Veil of 
head running out anteriorly into several cirri or tentaculiform 
lacinie. Two clavate tentacles. 
igus Loven. Tentacles vaginate, simple. 
Sp. Polycera punctilucens D’ORBIGNY, GUERIN Magasin de Zool. 1837, 
Mollusq. p. 106. 
Polycera Lovén. ‘Tentacles naked, annulate with transverse 
lamellee. 
Sp. Polycera cornuta, Doris cornuta ABILDGAARD, Zool. Danica, Tab. 145, 
figs. 1—3, Buainv. Malac. Pl. 46, fig. 10 ; according to Lovin Doris quad- 
rilineata MuEuu. Zool. Dan. Tab. 17, figs. 4—6, Tab. 138, figs. 5, 6, and 
Polycera ornata D’ORB., GUERIN Mag. 1.1. Pl. 107, ought to be brought 
under the same species. Comp. on this genus ALDER Annals of Nat. 
Hist. vi. 1841, pp. 337—342, Pl. 1x., Frey u. Leuckart Beitr. zur 
Kenntniss wirbell. Thiere, s. 66—7o. 
Tethys LL. Body somewhat oblong, depressed, furnished ante- 
riorly with a broad funnel-shaped, fimbriated veil, behind the veil 
contracted into a species of neck. Mouth proboscidious, retractile, 
in the bottom of velum. ‘Two conical tentacles at the base of 
velum, margined by a broad cup-shaped sheath. Apertures of 
generation and vent at the right side, in the anterior part of body. 
Two rows of branchie at the sides of back; cirrose pectinate 
branchiz alternating with smaller bundles. 
Sp. Tethys leporina L., RONDELET Pisc. p. 526, tertia leporis marini Species, — 
Cuv. Ann. du Mus. xi. pp. 259—270, Pl. 24, Mém. sur les Moll. vit., 
Buatnv. Malacol. Pl. 46 bis, fig. 9; in the Mediterranean; the Teth. fim- 
bria L., BonapscH De quibusd. Anim. marin., Tab. V. figs. 1, 2, appears 
not to differ from it. DELLE CHIAJE adopts two species, as does LINN2ZUS, 
Memorie, 111. p. 138, but his Teth. fimbria is not that of Linnzus, which is 
distinguished by the absence of filaments at the margin of the velwm. 
Triopa JOuNST. (species of Tritonta Cuy., species of Huploca- 
mus PHIL.). 
