OF NORTH AMERICA. 367 



RECORDS. 

 UNITED STATES. 



CALIFORNIA: Antioch, Contra Costa Co. (Carlton) ; San Antonio, San 

 Bernardino Co. (Lea) ; San Francisco, San Francisco Co. (Rowell) ; Alameda 

 Co. (Walker). 



WASHINGTON: Green Lake, Seattle, King Co. (Randolph). 

 BRITISH AMERICA. 



BRITISH COLUMBIA: Vancouver Island (Walker). 



GEOLOGICAL DISTRIBUTION : Unknown. 1 



ECOLOGY: Not recorded. The habitat relations of tryonii are 

 probably similar to those of palustris. 



REMARKS : Tryonii is quite a distinct little species, though related 

 to proximo,. It is always a smaller species than proximo, though hav- 

 ing about the same number of whorls, and the spire is not so elongated. 

 The sutures, also, are shallower and the whorls are more flat-sided. 

 It is not particularly related to palustris, being easily separated by its 

 smaller size, regularly conical spire, flattened whorls and by its regu- 

 larly ovate aperture. All of the specimens examined have a peculiarly 

 delicate yet distinct sculpture like an engine-turned surface. The 

 whorls vary somewhat in corpulency, and the aperture is more ovate 

 in some specimens than in others. The columellar plait is quite 

 prominent. Small specimens of palustris have been seen in various 

 collections from localities east of the Sierra Nevadas, which have been 

 labeled tryonii, but no authentic material has been seen from this 

 area. It has doubtless been reported as palustris from the region west 

 of the Rocky Mountains and a careful search through the collections 

 will probably widely extend the distribution, besides filling in many 

 blanks on the map. 



Lea first named this species traskii but later changed the name to 

 tryoniana on account of Tryon's traskii a distinct species named in the 

 previous year. Try on, however, used the name tryonii LEA, MS, in 

 1865 thus antedating Lea's name by a year. Lea's original specimens 

 are in the Smithsonian collection and compare favorably with the 

 specimens illustrated in this monograph. (PI. XXXIX, fig. 4, one of 

 the type specimens, No. 121470). The figure in Tryon's continuation 

 of Haldeman is not good as will be seen by a comparison with the 

 photograph of the type specimen. 



*In the fourth annual report of the Geological Survey of Texas (p. 188) 

 Mr. Singley records tryoniana as a fossil or subfossil from Tule Canyon, Swlsh- 

 er County, Texas. He says of it "Nearer this than any other species. Well 

 preserved shells, though bleached." The writer has not been able to examine 

 these shells, and he seriously doubts their being tryonii, authentic specimens 

 of which have not been seen from the great plains region. These specimens 

 were probably small or immature forms of palustris, which species has been 

 reported as a fossil from northern Texas. 



