I4O LAND AND FRESH WATER MOLLUSKS 



Stomach of sturgeon, Great Playgreen Lake, Keewatin, N. Lat. 54 . 



109 



III 



Fig. 109. Sphcerium tenue. 



Fig. ho. Sphcerium transversum Say, with foot and siphons extended. 



Fig. hi. Sphcerium lenticula. 



Sphaerium (Musculium) truncatum Linsley. 



Cyclas truncata Linsley, Am. Journ. Sci., vi, p. 234, fig. 3, 1848. 

 Sphcerium truncatum Prime, Mon. Am. Corbie, p. 51, fig. 50, 1865. 



Range. — Eastern United States from Colorado to Maine, south 

 to the Ohio River and northward to Athabaska. 



Methy Lake, Athabaska (Richardson). 



This species is quite similar to the European Cyclas calyculata, 

 type of the subgenus, and was mistaken for it by C. B. Adams in 1841. 



Sphaerium (Musculium) lenticula Gould. 



Sphcerium lenticula (Gould, MS.) Prime, Proc. Acad. Nat. Sci. Phila., 



for i860, p. 36 (syn. exclus.). 

 Sphcerium lenticula (Gould) Prime, Mon. Am. Corbie, p. 51, fig. 51, 



(syn. exclus.), 1865. 



Range. — Carson and Klamath Rivers, California; Nanaimo, Van- 

 couver Island, British Columbia. 



This species, named in MS. by Dr. Gould and described by Prime, is 

 not the same as the Lucina lenticula Gould, described from Patagonia 

 in the Mollusca of the Exploring Expedition. The latter, by an en- 

 graver's error, was called on the plate (but not in the text) Cyclas le?t- 

 tzcula, and this seems to have misled Mr. Prime, who may not have 

 had access to the text of this rare volume. 



* Sphaerium stagnicola J. de C. Sowerby. 



Cyclas stagnicola Sowerby, in Richardson, Fauna Bor. Am., Ill, p. 316, 

 1836, Methy Lake, Athabaska. 



* Sphaerium medium J. de C. Sowerby. 



Cyclas media Sowerby, op. cit., Methy Lake, Athabaska. 



The two names above cited from Sowerby are not described in 

 Richardson's work and I am unable to find any other reference to 

 them in the literature. I presume they are undescribed. 



