FAMILY SPH^ERIID^E 137 



Left bank of the Yukon River, Alaska, 30 miles below the mouth 

 of the Tanana ! In duck's crop at Fender Island, British Columbia. 



This attractive species is apparently sporadic or local in its habitats, 

 but if intelligently sought for would probably be found more often. 

 It is not yet positively known from British Columbia, but there is little 

 reason to doubt it will be found there when the fauna is better known. 

 So far it seems to be rather rare everywhere. 



* Sphaerium dentatum Haldeman. Figure 102. 



Cyclas dentata HALDEMAN, Proc. Acad. Nat. Sci. Phila., i, p. too, 1841, 



Willamette River, Oregon. 

 Spharium dentatum PRIME, Mon. Am. Corbie., p. 40, fig. 32, 1865. 



Range. California and Oregon. Spokane Falls, Washington. 



Sphaerium fabale Prime. Figure 103. 



Cyclas fabalis PRIME, Proc. Boston Soc. Nat. Hist., iv, p. 159, 1851. 

 Spharium fabalis PRIME, Mon. Am. Corbie., p. 40, fig. 33, 1865. 



Range. Eastern United States and northward, Battle River, 

 Alberta. 



This species was originally described from specimens collected in 

 Lake Superior by Louis Agassiz, but has since been recognized from 

 Georgia, Virginia and Tennessee. It is remarkable for its compressed 

 form and inconspicuous beaks. 



Sphaerium occidentale Prime. 



Cyclas avails PRIME, Proc. Boston Soc. Nat. Hist., iv, p. 276, 1852, not of 



FeYussac, 1807. 

 Spharium occidentale PRIME, Proc. Acad. Nat. Sci. Phila., for 1860, p. 295 ; 



Mon. Am. Corbie., p. 41, fig. 34, 1865. 



Range. Northern United States, Vermont to Washington and 

 northward. 



Hell Gate River (Columbia drainage), Montana! 

 Lower Saskatchewan River, near Lake Winnipeg; 

 Spokane Falls, Wash. 



*Sphaerium nobile Gould. FIG. 104. 



Cyclas nobilis GOULD, Proc. Boston Soc. Nat. Hist., v, p. 229, Sphcerium 

 1855 ; San Pedro, Cal. occidentale. 



Sphtzrium nobile PRIME, Mon. Am. Corbie., p. 41, fig. 35, 1865. 



Range. California, Washington, Idaho. 



Blackfoot River, Idaho ! Seattle, Wash. 



This is not figured by Gould in Expedition Shells, as stated by 

 Prime. It closely resembles S. dentatum Hald., but is less inflated, 

 while the young are smooth. 



