HANNIBAL: CALIFORNIA^ FRESHWATER MOLLUSCA. 131 



Sph^rium tence (Prime). 



Cyda^ tenuis, Prime, 1851 ; SphtBrium occidentale, Prime, 1860 ; 

 S. Uintaense, Call, 1886; S. TFalkeri, Sterki, 1901. 



Shell small, quadrate-discoidal, moderately compressed ; habitat 

 lakes and marshes. 



Boreal portions of Nearctic llegion. Yukon, Columbia, and Utah 

 Systems. 



Quaternary : Loess of eastern States. 



Sph^riom patellum (Gould). 



Cijclas patella, Gould, 1850 ; C. fahale, Prime, 1851 ; Sphcerium 

 Primeamim, Clessin, 1878. 



Shell of moderate size, quadrate-elliptical, somewhat compressed ; 

 habitat marsliy lakes and streams. 



Boreal portions of Xearctic Eegion. Fraser and Columbia Systems. 



Sph^rium (Amesoda) simile (Say). 



Cijclas similis, Say, 1817; C. striatina, Lamarck, 1818; C. staminea, 

 Conrad, 1834; C. clentata, Haldeman, 1841; C. aurea. Prime, 

 1851; C. solidula, Prime, 1851; C. nohilis, Gould, 1855; 

 SphcBfium Vermontamim, Prime, 1861 ; C. tumidum, Baird, 

 1863; S. ^sulcatum, Lam.', Keep, 1888; S. Sendersoni, Sterki, 

 1906; S. Pilshnjamim, Sterki, 1909; S. Kettlemanensis, Arnold, 

 1910; S. Cooperi, Arnold, 1910; not S. ' simih, Say', F. C. 

 Baker, 1898 = S. sulcatum, Lam. 

 Shell of moderate or large size, quadrate-trigonal, varying from 



moderately compressed to inflated, rather finely or coarsely striate ; 



habitat lakes, marshes, and streams. 



Xearctic Kegion. Fraser, Columbia, Klamath, Utah, Nevada, 



Colorado, Arizona, and Coast Range Systems. 



Quaternary : Loess of eastern States ; Bonneville Lake beds, Utah ; 



Lahontan Lake beds, Kevada. Pliocene : Santa Clara, Cache, and 



Kettleman Lake beds, California. 



Sph^rium (Amesoda) Idahoense (Meek). 



SpJmrmm (?) Idahoensis, Meek, 1870 ; S. rucjosum. Meek, 1870 (fig. of 

 type only = juv. individual). 



Shell very large, quadrate-trigonal, inflated, coarsely sparsely 

 striate ; habitat apparently lacustrine. 



Eocene : Truckee Lake beds, Nevada ; Payette Lake beds, Idaho. 



Sph^erium (Amesoda) Rogersi, n.sp. PI. VII, Fig. 21. 



Shell large, elongate-trigonal, moderatelj' inflated, coarsely striate ; 

 habitat apparently lacustrine. 



Length 20, breadth 14-5, depth of valves 9-5 mm. 



Eocene : local freshwater beds in Tejon formation, California. 



One-fourth mile above Carnegie Potterj^ plant, in cutting along 

 Western Pacific Railway, Corral Hollow, Tesla, California (Stanford 

 University Geological Survey, per W. H. Ochsner) (H. Hannibal). 



