AND OTHER FAMILIES. 207 



SECOND SUPPLEMENT. 



Read before the American Thilosophkal Society, February 1th, 1834. 



Unio Shepardianus. Plate XIII. fig. 38. 



Testd sublanceolatd, transversissimd, valde insequilaterali, antice rotundatd, 

 postice obtuso-angiilald, inferne emarginatd, ad latera planulatd ; cliro umboniali 

 elevato ; valvulis suba'assis ; natibus parvis, prope marginem anteriorem posilis ; 

 epidermide tenebroso-fuscd, obsolete radiatd ; dente cardinali obliquo, in valvuld 

 dextrd iinico, in sinistrd ditpUci ; dente laterali longissimo rectoque ; margaritd 

 purpitred et iridescente. 



Shell sublanceolate, very transverse, very inequilateral, rounded before, obtusely 

 angular behind, emarginate at base, flallened on the sides; umbonial slope elevated ; 

 valves somewhat thick ; beaks small and placed near the anterior margin ; epidermis 

 dark brown with obsolete rays ; cardinal teeth oblique, single in the right and double 

 in the left valve ; lateral teeth very long and straight ; nacre purple and iridescent. 



Hab. Hopeton, near Darien, Georgia. Professor Shepard. 



My Cabinet. 



Cabinet of Professor Shepard. 



Diara. 1, Length 1-4, Breadth 5 inches. 



Shell sublanceolate, very transverse, very inequilateral, rounded be- 

 fore, obtusely angular behind, emarginate at base, flattened over the 

 umbones and sides; umbonial slope forming an oblique ridge ; substance 

 of the shell rather thick ; beaks small and placed near to the anterior 

 margin ; ligament thin and long ; epidermis dark brown, almost black, 

 with obsolete rays on the more perfect individuals ; cardinal teeth erect, 

 single in the right valve and double in the left ; lateral teeth very long 

 and straight ; anterior cicatrices distinct ; posterior cicatrices confluent ; 

 dorsal cicatrices in the centre of the cavity of the beaks : cavity of the 

 beaks very shallow ; cavity of the shell deep under the umbonial slope ; 

 nacre beautifully purple and iridescent. 



