﻿GASTROCH^NA.— Platk II. 



large, almost extending to the end ; posterior side 

 trigonal, angular, depressed in front of the angle; 

 postei'ior area elevated, contabulated, deeply 

 wrinkled, broadly truncated at the end ; dorsal 

 area broad, expanded ; ligament large, short. 



Spekglee. Guerin, Mag. Hist. Nat. 



Hah. Isl. St. Thomas. 



Species 11. (Mas. Brit.) 



Gastroch^na Rupellii. Gas. testa crassd, nuhwcatu, 

 ivflatd, latere antieo ante umhones suhproclncio. 



qiutiiiposticHiii aiiijusiiusculo, tenuUer striato, nm- 

 hvnihus tiwiklissiniis ; medio Imvigato, striato ; 

 latere postico valide conceuiriee striato ; hiatu 

 i-('iitrali moderate arciiato. 



Rupell's Gastrochjina. Shell thick, subovate, in- 

 flated, anterior side rather produced in front of 

 the umbones, narrower than the posterior, finely 

 striated ; umbones very tumid ; middle smooth, 

 striated ; posterior side strongly concentrically 

 striated ; ventral hiatus moderately arched . 



Deshayes. Proc. Zool. Soc. 1854, p. 328. 



Hah. Red Sea. 



