SPH^ERIUM. 45 



Hob. North America, at New Orleans, La., and in Florida and Alabama. 

 (Cabinets of the Academy of Natural Sciences of Philadelphia and Prime.) 

 Cyclas elevata, HALDEMAN, Proc. Acad. Nat. Sci. Phila. I, 1841, 53. 

 Cyclas pallida, DECHARPENTIER, MSS. 1851. 



Remarkable for its transversely spherical shape, which renders 

 it distinct from all other species of this genus. It is much more 

 solid than the generality of calyculate species, the valves being as 

 strong as those of any of the larger species of the preceding group. 



C. pallida, the young of this species, is more delicate than the 

 adult ; it is a little less transversely spherical, the stria? are lighter, 

 and the color is bright yellow. 



Prof. Haldeman s original specimen of C. elevata, from which 

 this description was prepared, and which is now in the cabinet of 

 the Academy of Natural Sciences, though very perfect in appear 

 ance, comprised but a single valve. 



This species seems to be very rare. I have never met with any 

 other specimens but the one in the cabinet of the Academy and 

 those I have in mine two specimens of G. pallida, derived from 

 DeCharpentier himself, and a single valve from Florida. 



Fig. 41. 



S. elevatum. 



19. Sphaerium partumeium, SAY. Animal usually white, 

 in some varieties pink, syphonal tubes pink. 



Shell rounded-oval, thin, fragile, pellucid, somewhat inflated, nearly 

 equilateral ; anterior margin very slightly distend 

 ed, rounded ; posterior slightly abrupt ; basal 

 rounded ; beaks central, calyculate, approximate 

 at apex ; strise so delicate as hardly to be visible ; 

 epidermis glossy, of a light greenish horn color, 

 with at times a zone of a different shade on the 

 basal margin ; valves delicate, moderately convex, 

 interior light blue; hinge-margin nearly straight, 



passing by a regular curve into the anterior margin, 



J S. partumeium. 



but curving suddenly behind so as to form an obtuse 



angle, causing the posterior side to appear broader, thus giving the shell 



