56 NEW UNIONID^, MELANID^, ETC., 



undulate for some distance ; ligament long, narrow and light brown ; ej^idermis 

 yellowish green, obscurely rayed, with very distant marks of growth ; umbonial slope 

 but little raised, rounded ; posterior slope very much compressed, carinate, with two 

 slightly impressed lines in each valve, from the tips to the posterior margin ; cardinal 

 teeth rather small, compressed, crenulate and double in both valves ; lateral teeth 

 long, lamellar and straight ; anterior cicatrices distinct, large and well impressed ; 

 posterior cicatrices confluent rather large and slightly impressed ; dorsal cicatrices 

 jjlaced on the upper part of the cavity of the beaks ; cavity of the shell rather shallow 

 and wide ; cavity of the beaks shallow and obtusely angular ; nacre silver white and 

 iridescent. 



Bemarhs. — A single specimen only is before me. It cannot be confounded with 

 any species from Asia Minor I have seen. In outline and color of the epidermis it is 

 very much like some of our half grown white varieties of M. complanatus, but the 

 system of undulations of the beaks is totally different. These undulations cover a large 

 space as they do in Orantesensis, herein described, but there is a marked difference 

 in this characterization between the two, the Orontesensis having the undulations 

 crimpled, irregular and subconcentric, while Damascensis has them crimpled on the 

 anterior part, oblique and paralleled on the middle, and angular on the umbonial slope. 

 There is a well marked line of growth on the middle of the disk, but if this species 

 grows larger, as I believe it probably does, there may be additional ones on them. 



Unio Syriacus. pi. 19, fig. 63. 



Testa sulcata, subelliptica, inflata, valde insequilaterali ; valvulis subtenuibus, antice incrassatis ; natibus 

 prominentibus, tumidis; epidermide tenebroso-olivaeea, eradiata ; dentibus cardinalibus parvis, 

 acuminatis, subcompressis, in utroque valvule duplicibus; lateralibus parviusculis, lamellatis sub- 

 curvisque ; margarita albida et iridescente. 



Shell sulcate, subelliptical, inflated, very inequilateral ; valves rather thin, 

 thickened before ; beaks prominent, swollen ; epidermis dark olive, without rays ; 

 cardinal teeth small, pointed, somewhat compressed and double in both valves; 

 lateral teeth rather small, lamellar and somewhat curved; nacre whitish and 

 iridescent. 



Proc. Acad. Nat. Sci., 186.3, p. 189. 



Hah. — River Orontes, Syria, C. M. Wheatley. 



Cabinet of Mr. Wheatley. 

 Diam. "6, Length -8, Breadth 1-2 inches. 



Shell sulcate, subelliptical, nearly straight at the base, inflated, very inequilateral ; 

 substance of the shell rather thin, thickened before ; beaks prominent, swollen ; 

 ligament short and thick ; epidermis dark olive, inclining to brown, without rays. 



