THE NAUTILUS. 105 



V. lewisii Currier and V- sincera Say have been reported from 

 T^est of the Rocky Mountains, but it is probable that all the speci- 

 mens will prove to be V. humeralis. This is a somewhat variable 

 and badly misunderstood species. It is apparently widely dis- 

 tributed over all the Pacific slope. 



With the exception of V. humeralis all the species are abundant 

 wherever they occur, but they are sporadic. This species is also 

 sporadic but seldom occurs in large numbers. 



Valvata humeralis Say. 



Valvata humeralis Say. New Harm. Diss., II, 1829, p. 244. 

 Mexico. 



Valvata humeralis californica Pilsbry. Naut., XXII, 1908, p. 

 82. Bear Lake, Cal. 



Small, smooth, brown or blue-green, spire variable but always low, 

 umbilicus moderately broad, sutures slightly impressed. Character- 

 ized by a noticeable flattening about the umbilicus. 



The barely matured specimens from Bear Lake do not show this 

 character as noticeably as others in the writer's collection. This 

 species has been identified by west coast conchologists as V. virens, 

 V. lewisii, and V. sincera. The latter two can be easily eliminated 

 but the specimens from several of the localities given with a question 

 mark under V. virens may on re-examination prove to be V. humeralis. 

 Not known as fossil. 



Distribution.' 

 Mexico. 



California. 



* Bear Lake, San Bernardino Mts. (Berry). 



* Bluff Lake, San Bernardino Mts. (Berry). 



* Soap Lake, San Benito Valley (Hannibal). 



* Pond, Likely, South Pitt Valley (Hannibal). 

 Slough, De Witte, Honey Lake Valley (Hannibal), 



Oregon. 



* Upper Klamath Lake (Hannibal). 



Washi7igton. 

 Lake Washington, Seattle (Randolph). 



'* Seen by writer. 

 ? Identification doubted. ^ 



