CHIEFLY OF THE UNITED STATES. 255 



specimen ol semuugatus hefore me, — an authentic specimen from Bagdad, — given to 

 me at the " Museum" in Paris,* there are two sets of undulations, which meet and 

 make acute angles pointing to the tip of the beaks ; in the Emesaensis there are 

 three sets, and these make two sets of angles which point towards the basal margin. 



Unio maeginis. pi. 31, fig. 69. 



Testa loavi, ellijjtica, inflata, valde iutequilaterali, postice et antice rotundata ; valvulis crassiusculis, 

 antice crassioribus ; natibus subprominentibus ; epidermide striata, tenebroso-oliva, marginata, 

 obsolete radiata ; dentibus cardinalibus parviusculis, valde sulcatis et crenulatis ; lateralibus 

 subcurtis rectisque ; margarita alba et valde iridescente. 



Shell smooth, elliptical, inflated, very inequilateral, rounded before and behind ; 

 valves somewhat thick, thicker before; beaks somewhat prominent; epidermis 

 striate, dark olive, margined, obscurely rayed; cardinal teeth rather small, very much 

 sulcate and crenulate; lateral teeth rather short and straight; nacre white and 

 very iridescent. 



Proc. Acad. Nat. Sei. 1865, p. 89. 



Hah. — Blue Springs, Dougherty Co., Georgia, Bishop Elliott. 



My cabinet and cabinet of Bishop Elliott. 

 Diam. '5, Length 1, Breadth 1"1 inch. 



Shell smooth, elliptical, inflated, very inequilateral, rounded before and behind; 

 substance of the shell somewhat thick, thicker before ; beaks somewhat prominent ; 

 ligament very small, thin and light brown ; epidermis finely striate, dark olive, 

 obscurely rayed, with a well-marked greenish-j'ellow margin ; umbonial slope 

 rounded; posterior slope narrow and slightly carinate; cardinal teeth rather small, 

 very much sulcate and crenulate; lateral teeth rather short and straight; anterior 

 cicatrices confluent, rather small and deeply impressed ; posterior cicatrices confluent, 

 rather small and slightly impressed ; dorsal cicatrices placed in the centre of the 

 cavity of the shell ; cavity of the shell rather shallow ; cavity of the beaks shallow 

 and rounded ; nacre white and very iridescent. 



Remarks. — Only two specimens were received from Bishop Elliott. It belongs to 

 the group oi parvus, Barnes, but may easily be distinguished by its epidermis and 

 yellowish margin. It is not quite so transverse as parvus. The nacre of both 

 specimens is beautifully white and richly iridescent. Neither of the specimens are 

 perfect enough to show the undulations of the tips. When young, there may be rays 

 exhibited on the upper portions, but with these mature ones the yellow border only 

 slightly presents obscure green rays. 



* Baron Ferussac at the same time (1832) gave me a specimen from Bagdad under the same name, but which 

 evidently is distinct. It is oval, has irregularly corrugate beaks, epidermis olive, cardinal teeth compressed, 

 double in both valves, and has a white nacre. I have great pleasure in proposing the name U. Ferussacianus 

 for it, after the distinguished naturalist. 



65 



