HO AMERICAN MARINE CONCHOLOGY. 



white minute tubercles ; white, with a row of irregular bright- 

 yellow spots down each side ; branchial plumes ten, small, pin- 

 nated. 



Length 15, breadth 12 mill. 



New England, N. Europe. 



6. D. GRISEA, Stimpson. Fig. 225. 



Gould, Invert. Mass., 232, t. 20, f. 292, 295. 1870. 

 Body oblong-oval, covered with blunt processes tipped with 

 stellate clusters of spiculse; branchial plumes short, yellowish, 

 arranged in a circle around a dark bristle ; head short, broad, an- 

 gular. 



Length 13, breadth 9 mill. 



Massachusetts. 



Yerrill (Am. Journ. Sci., 1. 408, 1870) places this species in the 

 genus Onchidoris. 



7. D. BIFIDA, Yerrill. 



Am. Journ. Sci., 1. 406. 1870. 



Broadly oval, widest anteriorly, back very convex, mantle 

 covered with pointed papillae. Tentacles rather long, thickest in 

 middle, the outer half strongly plicated, but with a smooth tip, 

 the base surrounded by small papillae. Dark purple-brown, with 

 white spots ; the edges and tips of the gills yellow. 

 Length 1 inch, breadth J inch. 



Eastport, Maine. 



Genus DORIDELLA, Verrill. 

 Am. Journ. Sci., 1. 408. 1870. 



1. D. OBSCURA, Yerrill. Fig. 226. 



Am. Journ. Sci., 1. 408, f. 2. 1870. 



Broadly oval; back convex, smooth. Foot broad, cordate in 

 front. Oval disk broad, emarginate or with concave outline in 

 front ; the angles somewhat produced, forming short, tentacle-like 

 organs. Dorsal tentacles small, stout, retractile. Color blackish, 

 lighter towards the edge, as if covered with nearly confluent black 

 spots ; foot, dral disk, and dorsal tentacles white ; the central part 

 of the body, beneath, bright yellow. 



Length 7.5, breadth 5 mill. 



New Haven, Conn. 



