MARINE MOLLUSCA OF THE UNITED STATES. 109 



2. D. tenella Agassiz. Fig. 221. 



Gould. Invert. Mass., 2d edit. 229, t. 20, f. 289, 290, 293. 1870. 



Body ovate, coVered with small, pointed tubercles, 3 7 ellowish- 

 white ; branchial plumes six to seven, simple; mantle extended 

 anteriorly beyond the foot, head dilated laterally. 



Length half an inch, breadth three-eighths of an inch. 



Massachusetts. 



This and the following species are both referred b} r Verrill (Am. 

 Journ. Sci., ii. 407, 1870) to the genus Onchidoris, which differs 

 from Boris partly in the gills being retractile into separate cavi- 

 ties. 



3. I). AsrERA, Alder and Hancock. Fig. 222. 



Ann. Nat. Hist., ix. 32. 

 D. pallida, Agassiz, Proc. Bost. Nat. Hist., iii. 191. 1849. 

 Procta porta fusca, Morck. Grcenl. Bluddyr, G. 1857. 



Body elongated, sides parallel, ends equally rounded, covered 

 with large mushroom-like tubercles, cream-colored ; branchial 

 plumes seven to eight, simple, retractile. 



Length half an inch, breadth one-fourth of an inch. 



Gould calls this species D. pallida, Agassiz, and writes (Invert. 

 Mass, edit. ii. 230), " It is pretty certainly D. aspera, Alder and 

 Hancock, but if the exhibition of a colored drawing is a valid 

 claim, the name of Agassiz has precedence." If the drawing had 

 been p>ublished with a name attached to it, it would have secured 

 priority, but as it was merely shown at a meeting of the Boston 

 Society, the claim is simply ridiculous. 



Massachusetts. {Eur.) 



4. I). tuberculata, Cuvier, 180, 2, 1802. Fig. 223. 



D. diademata, Agassiz, Gould, Invert. Mass., 2d edit. 230, t. 21, f. 298, 300 

 to 304. 1870. 



Body oblong-oval, slightly broader anteriorby, maroon-color, 

 darkened on the sides by numerous dusky points, dark gray 

 below; branchial plumes nine, simple; head short, concentric, 

 pointed. 



Length one and a half inch, breadth nearly an inch. 



Massachusetts. 



5. D. repanda, Alder and Hancock. Fig. 224. 



Ann. Nat. Hist., ix. 32. 

 Doris planulata, Stimpson, Invert. Grand Manan, 26, f. 14. 1853. 



Body broad, mantle extended beyond the foot, covered with 



