BIVALVE SHELLvS. 267 



15. Sph.«;rium stramineum. 



S. testa ovata, regiilaiiter convexa, subsequilaterali, antice pos- 

 ticeque sequaliter convexa, fusco-virescente irregulariter sub- 

 striata ; umbonibus inflatis, obtusis vix prominentibus. 



Cvclas straminea, Conrad, Amer. Journ. xxix. 342. pi. 1. f. 5. 

 Mull. Syn. Test. Viv. p. 220. no. 1. 

 DeKay, Zool. New York, pt. 5. p. 225. 



Hab. In rivulis Alabamensibus. 



16. Sph^rium transvebsum. 



S. testa transversim oblonga, subovata, subsequilaterali, viridi, 

 substriata, antice rotundata, postice angustiore ; umbonibus 

 obtusis vix prominentibus. 



Cvclas transversa, Say, Descr. Land and Freshw. Shells, p. 10. 

 DeKay, Zool. Neiv York, pt. 5. p. 225. 



Hab. Kentucky, America; septentrionalis. 



17. Sph^rium giganteum. 



S. testa maxima, crassa, solida, subovata, complanata, sequilate- 

 rali, elongata, postice abrupta ; umbonibus magnis, non ele- 

 vatis. 



Cyclas gigantea, Prime, Proc. Bast. Sac. Nat. Hist. 1852, p. 15/. 

 Hab. In Pennsylvanise fluviis. 



18. Sph^rium emarginatum. 



S. testa magna, crassa, globosa, tumida, obliqua, postice sub- 

 truncata, inaeduilaterali, triangulari, epidermide olivacea, tenui- 

 ter striata; umbonibus tumidis, magnis, marginibus abruptis ; 

 dentibus crassis. 



Cyclas emarginata, Prme,Proc.Bos^Soc.iV«/.H2s<.1852,p.l56. 

 Hab. In lacu Superiore, Americse septentrionalis. 



19. Sph^rium tenuistriatum. 



S. testa subglobosa, complanata, brevi, subsequilaterali, postice 

 dilatata, tenuiter striata; umbonibus perelevatis; dentibus 

 parvis. 



Cyclas cornea, Adams (non Lamk.), Cat. of Shells in his Cabinet, 



1847. 

 Cyclas tenuistriata, Prime, Proc. Bost. Soc. Nat. Hist. 1852, -p. 156. 



Hab. In fluvio Tennessee dicto, Americae septentrionalis. 



12* 



