38 AMERICAN COBBICULAD^B. 







1851. The differences existing between these shells are at times 

 quite marked, but in general characters they agree, and 1 am in 

 clined to believe that these differences owe their origin solely to 

 local causes. 



I had occasion some time since to convince myself of the identity 

 of the S. striatinum with the C. edentula of Say. 1 



This species, which is not unplentiful in the localities where it 

 is found, varies much in size, color, and external appearance gene 

 rally. The shell from Connecticut is so slight, that it is nearly 

 translucent, and the striae are so light as to impart to it a lustrous 

 appearance ; on the other hand, I have specimens from the 

 Hoosack, which are quite heavy and coarsely striated ; in the 

 main, however, they all seem to tally. The variety from Alabama, 

 described as the C. tenuistriata, is less distended, is fuller, and 

 the sulcations are hardly perceptible. 



Compared with S. solidulum, this species is smaller, more in 

 equilateral, less tumid, more compressed, less solid, less heavily 

 sulcated, and its posterior extremity is more distended. 



6. Sphaerium stamiiieiim, CONRAD. Animal not observed. 



Shell oval, somewhat full, inequilateral ; anterior 

 Fig. 30. generally abrupt ; posterior slightly distended ; beaks 



very full and prominent, widely separate at the apex, 

 often eroded ; epidermis dark brownish-yellow ; stri?e 

 heavy ; valves strong ; interior blue ; hinge-margin 

 curved ; cardinal teeth double, nearly obsolete ; late 

 ral teeth distinct, strong. 



L.ong. 0.56 ; Lat. 0.37 ; Diam. 0.31 inches. 

 S. stamineum. 



Hub. North America, in the States of New Jersey, 



Ohio, Illinois, Arkansas and Alabama. (Cabinets of the Academy of Na 

 tural Sciences of Philadelphia, Smithsonian Institution, Conrad, Jay and 

 Prime.) 



Cyclas staminca, CONRAD, Amer. Journ. XXV, 1S34, 342, pi. 1, f. v. 



Cyclas fuscata, RAFINESQUE, Prime in Bost. Proc. IV, 1852, 281. 



Cyclas bulbosa, ANTHONY, Prime in loc. sub. cit. IV, 1852, 283. 



I have been induced to unite to this species the G. fuscata, 

 Rafinesque, which I consider as nothing more than a large variety, 



Notes on some American species of Cyclas, &c., by Temple Prime, 

 the Hague, 1857. 8vo. 



