for the Beccption of certain Species of Cassis. 215 

 21 



b 



Cypnecdssis rufa ; a, mature; b, immature. 



completes its outer lip but once during its life ; consequently, 

 it is destitute of varices. It has, also, no epidermis, nor is it 

 furnished with an operculum. In the latter characters it 

 approaches much nearer to the Cypras^adas, than to the 

 Cassides. 



Taking the Cassis rufa as the type of our new genus, upon 

 comparing it with Cyprae x a, and particularly with those di- 

 visions of that genus which are denoted by being rough on 

 the upper surface, including the striated and pustulated 

 species, we shall find in its shell such an affinity to these 

 latter, that, independently of the distinctness of its animal 

 from that inhabiting the true Cassides, we are only surprised 

 that an examination of the shell alone should not have at- 

 tracted the attention of conchologists to the necessity of 

 making the present separation. 



The principal distinction between this genus and Cypraexa 

 consists in the two lobes of the mantle of the animal not 

 meeting on the dorsum of the shell. Had the lobes of the 

 pallium in C. rufa extended so far as to have covered the 

 whole of the shell, as we find to be the case with nearly all 

 the cowries, the deposit of a smooth enamel-like coat, similar 

 to that of the inferior or basal surface, would then have ex- 

 tended itself over the rough surface of the upper portion, or 

 dorsum, including the recurved beak, or canal, and nearly 

 obliterating the spire ; would, in fact, have made it a perfect 

 Cyprae v a. 



