438 Annals of the Carnegie Museum. 



33. Sphaerium patella (Gould). 



Cyclas patella Gould, Boston Proc, III, 1850, p. 292. 

 Sphcerium patella Prime, Man. Corb., 1865, p. 42. 



Habitat. — ^Northern California to British Columbia. 



34. Sphaerium rhomboideum (Say) . 



Cyclas rhomboidea Say, Proc. Acad. Nat. Set. Philada., 1822, p. 380. 

 Sphcerium rhomboideum Prime, Mon. Corb., 1865, p. 39. 



Habitat. — New England, and New York, thence to Wisconsin; 

 Ontario; Manitoba; Alaska; British Columbia (?); Nevada (?). 

 Fossil. — Maine, Ohio, Michigan, Illinois. 



35. Sphaerium occidentale Prime. 



Cyclas ovalis Prime, Boston Proc, IV. 1852, p. 276. 



Sphcerium occidentale Prime, Proc. Acad. Nat. Sci. Philada., i860, p. 295; Mon. 

 Corb., 1865, p. 41. 



Habitat. — Widely distributed over the continent, but as yet of 

 doubtful occurrence in the southwestern states; apparently rare in the 

 south. 



Fossil. — This, or a species very close to it, occurs in the Miocene 

 of North Carolina. 



36. Sphaerium occidentale amphibium Sterki. 



Sphcerium occidentale am phibium Sterki, Proc. Ohio Acad. Sciences, 1907, p. 395. 



Habitat. — Extends over the same area as the preceding, but is 

 apparently more northern in its distribution. 



37. Sphaerium tenue (Prime). 



Cyclas tenuis Prime, Boston Proc, IV, 1851, p. 161. 

 Sphcerium, tenue Prime, Mon. Corb., 1865, p. 47. ^ 



This Sphceriiim is one of our rarest and least known species. Mr. 

 William F. Clapp in 1914 collected in Lake Champlain a number of 

 specimens of a form larger than any seen before, 7.5 to 9 mm. long. 

 The measurements are for example as follows: long. 8; alt. 6.5; diam. 

 4.5-4.8 mm. T. Prime in his Monograph gives the following measure- 

 ments: "Long. 4.5; alt. 3; dIam. 1.5 mm.," evidently being those of 

 an immature example. 



Habitat.- — Lake Chami)lain, Ontario, Michigan, northern Indiana, 

 Keewatin, Yukon Territory, Alaska. 



- Placed in the "Calyculate Group" = Musculium. 



