SPH^RIUM. 35 



This species was first described in 1818, by Lamarck, under 

 the names of G. sulcata nud C. saratoyea. Say, in 1819, igno- 

 rant that this shell was known to conchologists, described it as 

 the C. siviilis, under which name, until very recently, it has beeu 

 most generally known. Say also figured this species, but his 

 figure, I regret to say, is not coi-rect, and would be more apt to 

 give one the idea of a Pisidium than of a Sj:>hceriuni. The de- 

 scription by Say of the C. similis applies perfectly to the shell 

 under consideration, of which Dr. Gould has given a very good 

 figure in his Report on the Invertebrata of Massachusetts. 



As related elsewhere,* I had an opportunity, some years since, 

 while in Paris, to see Lamarck's original specimens of the C. sul- 

 cata and saratogea, at the Garden of Plants, and at the Delessert 

 Museum ; and to convince myself by examination that they both 

 belonged to one species, and were identical with Say's C. similis. 



2. Spliaeriuin aureilBll, Pkijie. — Animal not observed. 



Shell transversely oval, slightly elongated, nearly equilateral, heavy, 

 convex ; lieaks full, raised above the outline of the shell ; 

 anterior margin broad and rounded ; posterior narrower Fig* 26. 



and somewhat angular ; inferior slightly curved ; hinge- 

 margin somewhat broad, curved ; cardinal teeth diminu- 

 tive, double, so placed together as to represent the form of 

 the letter V reversed, and rather wide-spread ; lateral 

 teeth situated each one at an angle with the cardinal 

 teeth, strong and large ; sulcations deep, not very regular ; 

 epidermis varying from a greenish-yellow to a bright gold color, slightly 

 lustrous ; interior of the valves bluish-white. 



Long. 0.56; Lat. 0.43; Diam. 0.37 inches. 



Hah. North America, from Lake Superior? (Cabinets of Agassiz, 

 Smithsonian Institution and Prime.) 



Cijclas aurea, Prime, Bost. Proc. IV, 1S51, 159. 



This is one of our most attractive species, but also one of the 

 rarest. It is supposed to have been brought from Lake Superior 

 by the expedition which visited that region under Professor 

 Agassiz. In general outline it offers some similarities with the 

 S. sulcatum ; it is, however, a much more ponderous shell ; it is 

 less elongated, more convex, its sulcations are not so regular, its 



' Notes on some American species of Ci/clas, &c., by Temple Prime, the 

 Hague, 1857. 8vo. 



