MUSEUM OF COMPARATIVE ZOOLOGY. 347 



Section COCCULINA s. s 

 Cocculina Rathbuni Dall. 



Plate XXV. Figs. 5, 7, 7 a. 



Cocculina Rathbuni Dall, Proc. U. S. Nat. Mus. for 1881, p. 402, April, 1882. 



Shell white, depressed, the slopes flattened, sides subparalleled, with slight 

 radiating and concentric sculpture and a subcentral apex from which the 

 nucleus is usually lost, leaving a little scar on the shell. Length, 10-13 rum. 



Two female specimens examined, which had been a long time in alcohol. 

 The mantle margin appeared plain, with a thickened border. Behind in the 

 sinus between the mantle and the foot are two small round blunt elongated 

 epipodial papillae, one on each side of the median line and not very close to it. 

 The gill is small, triangular, exactly like that of some Acmaeas, and similarly 

 placed. The head is large, the end of the muzzle flat, marginated, semilunate, 

 enclosing a smooth space, in the centre of which is a rounded papillose area 

 surrounding the mouth; tentacles moderate, subcylindrical, without eyes; the 

 course of the intestine much resembling that of Patella, but it seems to be not 

 so long. Rhachidian tooth with a distinct cusp. 



This species was obtained by the U. S. Fish Commission in 1881, about 100 

 miles south and east from Martha's Vineyard, in 506 fms., green sand and 

 mud, the bottom temperature being 40°.5. The party on the Blake obtained 

 it at Station 288, in 399 fms., hard bottom, off Barbados, bottom temperature 

 44°.5 ; a fresh one at Station 230, in 464 fms., off St. Vincent, bottom tem- 

 perature 41°. 5; and living ones at Station 195, off Martinique, in 502^ fms., 

 sand and ooze, the bottom temperature being 41°. F. In the latter case the 

 animal was adhering to a small water-logged splinter. 



Cocculina Beanii Dall. 



Plate XXV. Figs. 2, 4, 8. 



Cocculina Beanii Dall, Proc. U. S. Nat. Mus. for 1881, p. 403, April, 1882. 



Shell elevated, white, the anterior slope much the longer and conspicuously 

 arched, the posterior slope excavated concavely, the apex elevated, subposterior 

 and much incurved, the nucleus generally gone in adults, leaving a little s"car; 

 sculpture stronger and more distinctly cancellated in some specimens than in 

 C. Rathbuni, the young are more sharply sculptured than the old, and at the 

 intersections the riblets are nodulous or even slightly spinose; the shell is 

 smaller than in C. Rathbuni, reaching about 8.0 mm. in length. 



Four specimens, all apparently females, were available for examination, of 

 which two were dissected. The soft parts in general were, as in C. Rathbuni, 

 except that the head and muzzle are much elongated, the sinus behind the 

 head, therefore, is deeper, the gill longer, projecting out on the right side; the 



