430 NEW GENUS AND SOME NEW SPECIES 



Say; and some of the younger and more ventricose specimens 

 assume the appearance of the U. triangularis. 



4. Unio Sulcatus. Plate VIII. fis:. 12. 



&■ 



Testa sub-ellipticd, inczquilaterali, ventricosd, sub-emarginala ; valvu- 

 lis crassis ; natibus fere terminalibus ; denlibus cardinalibus lateralibus- 

 que magnis, et duplicibus in valvulis ambabus ; margaritd purpurea. 



Shell sub-elliptical, inequilateral, ventricose, slightly emarginate; 

 valves thick; beaks nearly terminal ; cardinal and lateral teeth large, and 

 double in both valves; nacre purple. 



Hah. Ohio. T. G. Lea. 



My Cabinet. 

 Cabinet of T. G. Lea. 

 Cabinet of Prof. Vanuxem. 

 Cabinet of P. H. Nicklin. 

 Cabinet of the Academy of Natural Sciences. 

 Diam. 1-3, Length 1-7. Breadth 2-3 inches. 



Shell very thick, ventricose, inequilateral, obliquely longi- 

 tudinal ; margin sub-elliptical, with an emargination of poste- 

 rior basal margin, caused by a broad furrow running from the 

 beaks to this part of the margin ; substance of the shell thick 

 and ponderous ; beaks thick and projecting beyond the mar- 

 gin, nearly terminal, decorticated ; ligament partly concealed 

 by the beaks ; epidermis olive-brown, wrinkled, with nume- 

 rous fine hair like lines, which are slightly undulated, passing 

 from the beaks to the margin ; these lines are obsolete in the 

 anterior part of the shell, and crowded in the furrow, over 

 the umbonial slope they are proximate ; cardinal tooth eleva- 

 ted, conico-triangular, that in left valve deeply divided ; late- 

 ral tooth long, thick, and slightly curved, direction nearly 



be presumed, that the Mya margaritifcra of Linnaeus was in 1817 erected into a 

 new genus by Schumacher, under the name of Margaritana. If the absence of the 

 lateral tootli be sufficient to establish the genus, we must necessarily call it by 

 the Danish naturalist's name. 



