S T R yE A. 



Plate VII. 



Species 10. (Fig. a, i, Mus. Brit.) 



OstrjEa Columbiensls. Oft. testd compressd, Icevigatd, 

 invgulwiter subovatd, albidd, nonnunquam radiis 

 pinpureis dvplicatis ornaid, tenui ; valvuld inferiori 

 fnliaced ; cardine parvo, apice aciito ; iniiis albd, 

 mm-ginihus hitcralikis hmul dentinilatis. 



The Columbian Ostr^a. Shell compressed, smooth, 

 irregularly subovate, whitish, sometimes orna- 

 mented with duplicate purple rays, thin ; lower 

 valve foliaceous, hinge small, apes acute ; white 

 within, with the lateral margins not denticu- 

 lated. 



Hanlev. Pro. Zool. Soc. 1845. 



Hah. St. Helena, Cuming. iMazatlan. Lower California. 



It is difficult to distinguish shells of this variable 

 species from young specimens of Ostrwa rostrata. They 

 are, however, believed to be different by those who 

 have studied every series of both species in various 

 stages, and when tolerably free in their growth their 

 tendency seems to be rather towards an oval than a 

 triangular form. 



January 



Species 11. (Mus. Ilanley.) 



OsTRJ2A Belcheri. Ost. testd 7na.nmd, compressd, spa- 

 thulatd, elongato-suhtrigond, crassmsculd, foliaced, 

 squamis maximis, quadratis, purpureo-subviridis ar- 

 matd ; valvuld inferiori planidatd, superiori con- 

 vexd ; cardine lata ; margine ventrali expan^o. 



Belcher's Ostr^a. Shell very large, compressed, 

 spathulate, elongate-subtrigonal, rather thick, 

 foliaceous, armed with very large, square, rather 

 purplish green scales ; lower valve flattened, 

 upper convex ; hinge broad ; ventral margin ex- 

 panded. 



Sowerbt. 



Hub. Eastern Seas ? — Captain Belcher. 



It is to be regretted that this magnificent shell, now 

 in the collection of Mr. Hanley, has had no specific 

 locality assigned to it by Captain Belcher, who brought 

 it home among the fruits of his expedition. It is re- 

 markable for its large flat scales. The specimen is 

 attached to a broad flattened stem of mangrove. 



, 1871. 



