54 NEW UNIONID^, MELANIDiE, ETC., 



Shell smooth, quadrate, inflated, very inequilateral ; substance of the shell some- 

 what thick, thicker before ; beaks somewhat prominent, closely and minutely undu- 

 late at the tips ; ligament rather short and brown ; epidermis reddish brown, dark on 

 the posterior slope, obscurely rayed, with four or five rather distant marks of growth ; 

 umbonial slope somewhat raised and rounded; posterior slope rather broad and 

 somewhat carinate ; cardinal teeth rather small, compressed, crenulate and double in 

 both valves ; lateral teeth long, lamellar and nearly straight ; anterior cicatrices dis- 

 tinct and well impressed ; posterior cicatrices confluent and very slightly impressed ; 

 dorsal cicatrices placed on the upper pai't of the cavity of the beaks ; cavity of the 

 shell rather deep and wide ; cavity of the beaks rather shallow and obtusely angular ; 

 nacre whitish with a very pale purplish hue posteriorly. 



RemarTcs. — Two specimens of this rather small species are before me. The beaks 

 are beautifully sculptured over all the upper part, the undulations being very regular 

 and very distinct. It reminds one of Batavus, Lam., but it is quadrate, while Batavus 

 is oval and disposed to obliqueness. It is more inflated in the middle and the undu- 

 lations of the beaks are finer and more numerous. The anterior portion of both 

 specimens is white while the posterior is faintly purplish and very iridescent. One 

 of them is slightly salmon colored in the cavity of the beaks. In outline it is near to 

 Bruguieriamis, Bourg., but it is rather more quadrate, more inflated, of a darker color, 

 and has undulations at the tips which are not mentioned by M. Bourguignat in his 

 species. His M. Vescoi and Schioerzeribacldi have raised striae on the beaks, but the 

 character of them is totally different from Orontesensis. 



UnIO BoURGUIGlSrATIANTJS. PL 18, fig. 51. 



Testa Isevi, obliqua, inflata, inEequilaterali, ad latere parum planulata ; valvulis percrassis, antice crassiori- 

 bus ; natibus prominentibus, tumidis ; epidermide straminea, eiadiata ; dentibus cardinalibus mag- 

 nis, erectis, in utroque valvule duplicibus, subcompressis, corrugatis crenulatisque ; lateralibus prse- 

 longis, crassis, corrugatis subcurvisque ; margarita alba et valde iridescente. 



Shell smooth, oblique, inflated, inequilateral, somewhat flattened at the side; 

 valves very thick, thicker before ; beaks prominent, swollen ; epidermis straw color, 

 without rays; cardinal teeth large, erect, and double in both valves, compressed, 

 rough and crenulate ; lateral very long, thick, corrugate and somewhat curved ; nacre 

 white and very iridescent. 



Proc. Acad. Nat. Sci., 1863, p. 189. 



Eah. — Tigris Eiver at Mosul, Asia Minor, C. M. Wheatley. 



My cabinet and cabinet of Mr. Wheatley. 

 Diam. 1-1, Length 1-6, Breadth 2-9 inches. 



Shell smooth, oblique, inflated, inequilateral, slightly flattened at the side, round 



