PILEOLUS 



TESTA patelliformis, vertice subcentrali, recto* 

 Discus inferus, parte central! pulvinulata; 

 apertura exigua, sublaterali, semilunari, labio 

 externo marginato, interno crenulato. Spira 

 omnino interna, brevissima. 



A NEW Genus of shells related to Nerita which has been 

 discovered about a twelvemonth since by the Rev. George 

 Cookson^ who has named it Pileolus, from its resemblance 

 to a little cap. For some time we hesitated about its re- 

 lative situation, because in its general form it so exactly 

 resembles the Patellce, while the structure of its inferior 

 disk is so unusual in appearance, that it was not until we 

 had broken one, and thereby discovered its internal spire^ 

 that we concluded upon its relation to Nerita ; we had 

 even at one time a suspicion that it might prove to be a 

 bivalve, something like Hipponyx ; but this suspicion was 

 founded upon the examination of a specimen, which we 

 are now persuaded, has some very young oysters attached 

 to its upper surface. 



Shell of an obtusely conical form, with a nearly re- 

 gularly orbicular base, and its vertex very nearly central 

 and upright. In the lower disk, of which the center is 

 rather prominent and cushion shaped, is placed the small 

 rather lateral, semilunar aperture, whose internal lip is 

 crenulated, and whose external lip has a raised margin. 

 The spire is entirely internal and very short. 



Of this interesting and indeed singular Genus only 

 two species have been found, both of which are named 



