SPH^RIUM. 45 



Hah. Nortli America, at New Orleans, La., and in Florida and Alabama. 

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

 Cyclas elevaia, Haldemax, Proc. Acad. Nat. Sci. Phila. I, 1841, 53. 

 Cijclas pallida, DeChakpextier, 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 striae are lighter, 

 and the color is bi'ight yellow. 



Prof. Haldemau's original specimen of G. elei:ata, from w^hich 

 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. elevntum. 



19. Spliseriuiii partimieiiim, Sat.— Animal usually white, 

 in some varieties pink, syphoual tubes pink. 



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

 equilateral ; anterior margin very slightly distend- 

 ed, rounded ; posterior slightly abrupt ; basal ^'S- 42. 

 rounded; beaks central, calyculate, approximate ,,«iBii^^|fcfe. 

 at apex ; strije so delicate as hardly to be visible ; j^m^^:^^^mts. 

 epidermis glossy, of a light greenish horn color, / 

 with at times a zone of a dififerent shade on the t; 

 basal margin ; valves delicate, moderately convex, 

 interior light blue; hinge-margin nearly straight, ''^^^--r"^, 

 passing by a regular curve into the anterior margin, ^^ pm-t^nuUiua. 

 but curving suddenly behind so as to form an obtuse 

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



