108 AMERICAN MARINE CONCHOLOGY. 
Synopsis of Genera. 
Subfamily Dorrpin &. 
Body depressed, rounded above ; mantle convex, large, simple, cover- 
ing the head and foot. 
Tentacles dorsal, subclavate, laminated, retractile within a cavity ; 
gills arborescent, retractile ; vent in the centre of the gills. 
Doris, Linneus. 
Body covered with an ample, smooth mantle, oval, convex; dorsal 
tentacles retractile, without sheaths; head prominent, the lateral 
angles prolonged anteriorly as short oval palpi or tentacles; foot 
broad, cordate ; branchiz posterior, in the groove between the man- 
tle and foot. DoriIDELLA, Verrill. 
Subfamily PoLycERIN&. 
Body elongate, subangular; mantle indistinct. 
Body smooth or tuberculated ; tentacles clavate, pectinate, non-re- 
tractile, without sheaths ; a frontal veil with simple processes on the 
head ; gills with two or more lateral appendages. 
Pouycera, Cuvier. 
Genus DORIS, Linnzus. 
Syst. Nat., edit. x. 653. 1758. 
The branchial plumes form an elaborate coronal around the 
vent, which, viewed with a common lens in a vessel of water, 
forms, when fully expanded, a beautiful object. The surface of 
the mantle is either smooth or tubercular, and the sheaths of the 
tentacles are often crenate on their margins. 
1. D. BILAMELLATA, Linneeus. Fig. 220. 
Syst. Nat., edit. xii. 1085. 1767. 
Doris fusca, Muller, Zool. Dan. Prodr. 229. 1780. 
Doris verrucosa, Pennant, Brit. Zool., iv. 43, t. 21, f. 28. 1777. 
Doris vulgaris, Leach, Syn. Moll. Gr. Brit. 19. 
Doris Elfortiana, Leach, Ibid., 20, t. 7, f. 1. 
Doris affinis, Thompson, Ann. Nat. Hist., v. 85. 
Doris liturata, Beck, Moller, Ind. Moll. Groenl., 5. 
Doris obvelata, Bouchard, Cat. Moll. Boul., 42. 
Doris coronata, Agassiz, Proc. Bost. Soc. Nat. Hist., iii. 191. 
Body elliptical, covered with pestle-shaped papille, whitish 
varied with rusty brown or flesh-color, and opaque white; branchiz 
twenty to twenty-five, long, linear, simply pinnate, arranged trans- 
versely in an oval, including several tubercles. 
Length about an inch, width half an inch. 
New England to Greenland, N. Europe. 
