424 Deep-sea Trawling off the 8,W. Coast of Ireland: 



just in front of the central part stronger than those down 

 the anterior side and the few upon the rostrum, which is 

 truncate at the end and well marked off from the rest of 

 the shell by a conspicuous contraction in the lower margin. 

 Length 7, height 3f millim. 



From 1 000 fath. 



Only a single specimen of this species was obtained. It is 

 peculiar for the straightness of the hinge-line. In this 

 respect, to some extent, it resembles the figure of Cardiomya 

 perrostrata, Dall (Bull. Mus. Comp. Zool. Harvard, vol. xii. 

 pi. ii. figs. 3 a, 3 J) . That species, however, is distinguished 

 by a somewhat longer rostrum, and the main portion of its 

 valves is more globular. 



Nuculana pusio {VhXYx^Yi)'^ 



From 1000 fath. 



Several specimens from this locality I cannot distinguish 

 from others obtained by the ' Porcupine ' expedition, which 

 were named Leda pusio of Philippi by Jeffreys. With this 

 determination, however, I am not at all satisfied, for both the 

 description and figure of Philippi indicate a shell of a con- 

 siderably different form. I have not had an oppoi'tunity of 

 seeing fossil examples, upon which the species was founded, 

 and therefore hesitate to separate the recent specimens as a 

 distinct species. 



I feel compelled to adopt the generic term Nuculana not- 

 withstanding the observations of Mr. Dall *. 



Morch t in his paper " On the genera of Mollusca 

 established by H. F. Link," arrived at a similar conclusion. 



Dall has translated " Die Schalen gleich, schliessen 

 iiberall " (part of Link's diagnosis) thus : " shell smooth, 

 closed all round," and states that this " will not apply to the 

 group separated by Schumacher, afterwards, under the name 

 of Leda^ The correct rendering of the above sentence I 

 believe should be the valves equal [or alike) closed all round J, 

 terms which do apply to the only species quoted by the 

 author, namely, N. rostrata, wdiich is synonymous with 

 N. pernula of MllUer, under which name this species is now 

 usually known. 



As Nuculana has some years precedence over Leda, in 

 Mr. Dall's words, it " must necessarily be adopted. The 

 longer an untenable name is retained, the more inconvenience 



* Bull. Mus. Comp. Zool. 1886, vol. xii. p. 245. 

 t Proc. Zool. See. Lond. 1862, p. 228. 



X It is uot probable that notice was taken of the very slight chink at 

 the end of the rostrum. 



