DORIS. 229 



This is widely distributed, and very variable in size and color, and 

 also in the number of the branchial plumes ; hence the great num- 

 ber of names which have been applied to it. Our specimens vary so 

 much from the figures given by Alder and Hancock that I should 

 hesitate to consider them the same, did not Dr. Stimpson assure me 

 that they arc identical with specimens dredged by him on the coast 

 of England. 



Doris tenella. 



Plate XX. Figs. 289, 290, 293. 



Body ovate, covered with small, pointed tubercles, yellowish-white ; branchial 

 plumes six to seven, simple ; mantle extended anteriorly beyond the foot, head 

 dilated laterally. 



Doris tenella, Agassiz, Proc. Best. See. iii. 191 (1850), no description. 



Body ovate, broadest in front, of a yellowish-white, translucent 

 color, covered with very numerous small, pointed, opaque white tu- 

 bercles. Tentacles long and slender, with about fourteen oblique 

 lamintB occupying nearly their whole length. Branchial plumes sim- 

 ple, short, six or seven in number. Foot elliptical, bluntly rounded, 

 extending a little beyond the mantle, lemon-yellow, with a central 

 orange blotch. Head short, rather broader tlian foot, pointed at 

 angles, and somewhat bi-lobed in front, broadly shielded by the 

 mantle. Length, half an inch ; breadth, three eighths of an inch. 



Found by Professor Agassiz at Beverly, February, 1848. 



Tlie above characters are drawn from a figure made of a single 

 specimen, without any detailed description. The animal is delicate 

 and almost transparent, and quite remarkable for the broad expan- 

 sion of the anterior part of the mantle beyond the foot, and for the 

 lateral dilatation of the head itself, and its angular form. Were 

 the means at hand of examining the tongue, spiculoe, and other con- 

 ditions, it might be found identical with some European species. It 

 seems to approach most nearly to D. inconspicua, Alder and Han- 

 cock, and is not very different from D. pusilla. 



Doris pallida. 



Plate XX. Figs. 284, 287, 288, 291. 



Body elongated, sides parallel, ends equally rounded, covered with large, mush- 

 room-like tubercles, cream-colored ; branchial plumes seven to eight, simple, re- 

 tractile. 



