Sterki: North American Sph.^iRiid.e. 441 



10. Musculium jayense (Prime). 



Cyclas jayensis Prime, Boston Proc, IV, 1851, p. 157. 

 Spharium jayaniim Prime, Man. Corb., 1865, p. 46. 



Habitat. — Ohio to Dakota, Ontario, Manitoba, Alberta. 



11. Musculium partumeium (Say). 



Cyclas partumeia Say, Journal Acad. Nat. Set. Philada., II, 1822, p. 380. 

 Sphcerium partumeium Prime, Mon. Corb., 1865, p. 45. 



Very variable, and there appear to be some more or less well-marked 

 varieties, besides those hereafter mentioned. 



Habitat. — East of the Rocky Mountains, commoner in the northeast. 



12. Musculium partumeium coeruleum (Prime). 



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

 Habitat. — New England, New York. 



13. Musculium partumeium globosum var. no v. 



Small, well inllated, with rounded, almost circular outlines. 



Measurements. 



Long. 8.3; alt. 7.5; diam. 5 mm. (100 : 90 : 60) Massachusetts. 

 Long. 7.3; alt. 6.8; diam. 5 mm. (100 : 93 : 68) Ohio. 



Habitat. — Duxbury, Massachusetts, collected by Mr. William F. 

 Clapp in 1913, specimens in the Museum of Comparative Zoology 

 and in the Carnegie Museum, No. 7885; Rhode Island; Garrettsville, 

 Ohio, collected by Mr. George J. Streator, 1900, Carnegie Museum, 

 No. 1914. All specimens from whatever locality are markedly uni- 

 form. 



14. Musculium partumeium mirabile (Prime). 



Cyclas mirabilis Prime, Boston Proc, IV, 1851, p. 157; treated in the Monograph 

 of the Corbiculadce as a synonym of Sphcerium partum.eium. 



Habitat. — Georgia, Florida. 



15. Musculium partumeium eburneum (Anthony). 



Cyclas eburnea Anthony, Boston Proc, IV, 1852, p. 279. Synonym of Sphcrriunt 

 partumeium Prime, Mon. Corb. 



Habitat. — Arkansas. 



16. Musculium truncatum (Linslcy). 



Cyclas truncala Linsley, Am. Jour. Sci., VI, 1848, p. 234, fig. 3. 

 Cyclas pellucida Prime, Boston Proc, IV, 1851, p. 277. 

 Sphcerium truncatum Prime, Mon. Corb., 1865, p. 51. 



