L.YMNJEIDM OF NORTH AMERICA. 369 



Type : Academy of Natural Sciences, Philadelphia, Pa., one speci- 

 men, No. 58519. 



Type Locality : Mountain lake, California. 



Animal, Jaw, Radula and Genitalia : Not examined. 



Range: (Figure 39) California to Wyoming, north to southern 

 Alberta. A species characteristic of the Upper Austral Transition and 

 Boreal (Canadian) life zones and of the Calif ornian, Coloradoan and 

 Hudsonian regions. A careful search will doubtless fill the vacant 

 territory between Wyoming, California and Alberta. 



RECORDS. 

 United States. 



California: Oakland and Berkeley, Alameda Co. ( Cocker ell ) ; mountain 

 lake near San Francisco, San Francisco Co. (Hemphill; Rowell; Tryon; Wood) ; 

 Santa Clara Co. (Stearns). 



Wyoming: Black Rock Butte, Sweetwater Co. (W. C. Knight; Walker). 

 British America. 



Alberta: Banff (Bos. Soc. N. H.). 



Geological Distribution : Unknown. 



Ecology: Not recorded. 



Remarks : Traskii may be known by its short spire, very large, 

 rotund body whorl and distinct umbilical chink. The inner lip is 

 broadly reflected and without a distinct plait, resembling in this re- 

 spect such species as cubensis, galbana, etc. It is this resemblance 

 which has led some conchologists to place traskii in the synonymy of 

 galbana, an erroneous disposition as it is clearly a member of the 

 subgenus Stagnicola and is closely related to proxima, which occasion- 

 ally has a raised inner lip and a small chink. The flat, smooth ex- 

 pansion of the inner lip is not always a safe guide as this occurs in 

 typical palustris (from Colorado) as well as in certain species of the 

 emarginata group, which are undoubtedly members of the subgenus 

 Stagnicola} 



The study of Tryon's type and of the material in Philadelphia, 

 Washington and in certain private collections, renders it apparent that 

 traskii is a distinct species and not a variety of proxima as thought 

 by Tryon. No specimens have been seen which connect the two 

 species although they occupy the same territory. The sudden en- 

 largement of the body whorl, the wide, smooth inner lip, the con- 

 spicuous umbilical chink, and the short, almost shouldered spire, are 

 characteristics which separate traskii from proxima. Von Martens 

 cites the species from Alaska, but this record needs confirmation. 



■An examination of the radula will at once settle the question of its 

 proper position, Stagnicola having bicuspid laterals while the group of which 

 galbana is a member has tricuspid laterals. 



