194 THE PTEROPODA 



their entire length (fig. 12), rounded in the posterior 

 third of the shell. Seen from the left or the right, the 

 shell shows its sides markedly separated off from the rest 

 (fig. 12), and not symmetrical but directed somewhat ven- 

 trally. Embryonic shell separated by a distinct constriction, 

 proportionally large, pointed. 



Animal with a bilobed fin and a short appendage on 

 either side of the mantle. 



I shall not bestow a name upon this form, as it is almost 

 certainly a young stage. Nevertheless, it may be of im- 

 portance to note that it cannot be referred, in my opinion, 

 to any known species. The shape of the embryonic shell 

 is much like that of Clio cuspidata^ but here it is much 

 more pointed. Tbe flattened lateral sides indicate a species 

 in which this flattening extends to the neighbourhood of 

 the embryonic shell ; and this, together with the shape of 

 the last, suggests that it may be a young stage of Clio 

 balantium^ in which the longitudinal ribs and the charac- 

 teristic transverse sculpture have-not yet quite appeared. 

 But the corresponding place of the adult shell of C. halan- 

 tium shows the difference of being more high than broad 

 in transverse section. There is also a great resemblance to 

 Clio chaptali Souleyet, the nearest relative to C. balantinm, 

 but here the sides are not flattened, but sharply-keeled, 

 and the whole shell is proportionally broader. 



Genus 5. Cuvierina Boas. 

 Species 1. Cuvierina columnella (Rang). 



Animals: 



Indian Ocean, (14" S., 114-^ E.), 1S80, 5 sp., R. J. Lusink. 

 // (32" S., 42" E.), 1879. 1 sp., ,/ 



Empty shells : 



ISl. Atlantic Ocean (Florida), date?, 6 sp., H. B. Preston. 



Japan, date?, 1 sp., v, Siebold. 



W. Pacific Ocean, purchased 1907, 6 sp., Sowerby & Fulton. 



Notes from the Leyden IVIuseum, Vol. XX.IX. 



