53 



dispor.ed as to pve that part of the spire nine sides : the 

 turns are not easily distinguished from each other, except 

 by the larger row of tubercles. 



Out of the upper marine stratum at Headon Hill, 

 where it is abundant ; it resembles Murex turbinatus of 

 Brocchi, p. 443, but is evidently distinct. 



POTAMIDES ventricosus. 



TAB. CCCXLl.— Fig. 1. 



Spec. Char. Conical, tun-eted ; whorls ventricose, 

 costated, transversely striated ; stria; two or three 

 upon each whorl, most elevated upon t!ie costse ; 

 aperture orbicular, with an extremely short beak. 



A SMALT, well circumscribed species ; the striae that 

 cross the costee upon the spire almost divide each of 

 them into three tubercles : there are two more striae upon 

 the base which is convex ; the orbicular aperture appears 

 to have no furrow even within its upper part ; the colu- 

 mella is smooth, and the beak obscure. 



This gregarious shell is very abundant in some parts 

 of the so called upper marine formation of the Isle of 

 Wight, accompanied with hardly any other shell except 

 the last species. I have received it also from France, 

 but without a name. 



POTAMIDES acutiis. 

 TAB. CCCXU.— Fig. 2. 



Spec. Char. Conical, turreted ; whorls convex, hica- 

 rinated ; carina? acute ; base convex, histriate<l ; 

 aperture orbicular, with a narrow short beak. 



ABOUThalf an inch long ; an elegant, smooth, sharply 

 carinated species. 



Discovered in a thin bed belonging to the lower fresh 



