6 



% 



Animal, not observed. 



Shell transversely inequilateral, elongated, slightly convex ; beaks full, not 

 very prominent ; anterior margin rounded ; posterior drawn out to an angle ; 

 base slightly curved ; epidermis variable, dark chestnut or brownish yellow, 

 with sometimes a yellow zone on the basal margin ; sulcations coarse, irregu- 

 lar ; interior dark blue ; hinge margin considerably curved ; cardinal teeth 

 double, in the shape of the letter V reversed ; lateral teeth large ; the anterior 

 placed at an angle with the margin ; the posterior more on a continuation of 

 the curve. 



Long. 9-16 ; lat. 7-16 ; diani. 5-16 inches. 



Hob. North America, in the States of New York, New Jersey, Ohio, Mary- 

 anl, Virginia and Indiana. 



(Cabinets Academy of Nat. Sci. of Phila., Jay et Prime.) 



This species which is not uncommon was probably confounded by our early 

 oouchologists with the Sph. s u 1 c a t u m, it differs from that shell, however, in 

 being less elongated, more inequilateral, less convex, the hinge margin is 

 more curved, and the shell is more solid. 



4. Sph. striatinum, Lam. 



Cyclas striatina, Lam., An. s. vert., v. 560, 1818. 

 C. edentula, Say, N. Harm. Dissem. 2, 1829. 

 C. cornea, Lam., C. B. Adam's Cat., 1847. 

 (7. albula, Prime, Bost. Proc. iv. 155, 1851. 

 C. tennistriata, " loc. sub. cit., iv. 156, 1851. 

 C. acuminata, " " " iv. 158, 1851. 



C. inornata, " ' " iv. 159, 1851. 



C. simplex, " " " iv. 159, 1851. 



C. modesta, " " iv. 159, 1851. 



Animal white, tubes light reddish yellow. 



Shell slight, transversely elongated, somewhat compressed, inequilateral ; 

 anterior margin rounded, posterior distended, inferior rounded ; beaks full, 

 not much raised ; sulcations irregular, at times so light as hardly to be seen 

 with the naked eye, thus giving the shell a lustrous appearance ; color vary- 

 ing from a light greenish yellow to a darker shade ; valves slight ; interior 

 blue ; hinge margin slightly curved ; cardinal teeth double, very small, of 

 the same size ; lateral teeth larger, not very prominent. 

 Long. 7-16 ; lat. 5-16 ; diam. 4-46 inches. 



Bab. North America, in the States of New York, Connecticut, Pennsyl- 

 vania, Michigan, Illinois, Ohio, Alabama, Tennessee, and in the Hell Grate 

 river, Washington Territory. 



(Cabinet. Academy of Nat. Sci. Phila., Jay, Prime and others.) 

 As may be seen by the above synonymy, I have been induced to unite under 

 this species several which I described as distinct in 1851. The differences ex- 

 isting between these shells are at times quite marked, but in general charac- 

 ters they agree, and I am inclined 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 

 Sph. striatinum with the Cyclas edentula of Say.* 



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

 varies much in size, color and external appearance generally. 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 spe- 

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

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

 bed as the Cyclas ten u is tr iat a, is less distended, is fuller, and the sul- 

 cations are hardly perceptible. 



,o* Jot o S on 80une Am encan species of Cyclas, etc., by Temple Prime. The Hague, 



lOOY. OVO. 



