RICINULA. 



just witbin the outer lip: there are scarcely any traces of 

 these in the young shells of some species, but, as the 

 shells increase in thickness, regular single teeth are 

 formed, and at their full growth the upper one of these 

 consists of four lobes, the next of two or three, and the 

 remainder only are single; in this state these teeth pro- 

 ject so far across the aperture as to give it a sinuous and 

 contracted appearance. The folds or teeth near the base 

 of the columella are very irregular; in some species 

 scarcely observable, in others very strongly marked. 



This Genus is marine ; its species do not appear to be 

 very numerous ; the Murex neritoideus is the Linnean 

 type of the Genus. 



We have never seen any fossil species. 



Fig. 1. Ricinula horrida, Lam. 



2. - 



3. - 



4. - 



5. - 



— Moms. 



digitata. 



var. 



arach.oidss, testa jun. 



