288 WEST COAST SHELLS 



white {peristome oi the typical specimens; diameter, 

 20 mm. 



F o I y (J y r a colinnbiana^ Lea, the 

 Columbia Snail, Figure 277, is a spe- 

 cies which extends irom Alaska south- 

 Fig. 277 ward into California. Whorls six, um- 

 bilicus small, peristome reflected, aper- 

 ture ear-shaped. In some varieties, as shown in the 

 cut, there is a small white tooth on the inner wall 

 of the aperture. The hgure is of the natural size. 

 The shell is light horn-colored, and the epidermis 

 on the upper whorls is set with short, stiff, micro- 

 scopic hairs. Var. armigera, Ancey, is smaller, more 

 globose and convex beneath, and more beset with 

 hairs, which are arranged in very oblique rows, Var. 

 lahiosa, Gld., has a nearly circular aperture and 

 widely reflected peristome. 



Polygyra devia, Gld., the Devious Snail, is a spe- 

 cies which lives in Oregon; it has also crossed the 

 Cascade Mountains and entered Idaho. The shell 

 is horn-colored or brown, solid and six-whorled. The 

 peristome is white, wide, and bent back at right 

 angles to the wall of the aperture. There is a dis- 

 tinct white tooth on the inner wall ot the aperture, 

 and sometimes one or more waves on the peristome. 

 There are several varieties which range irom half an 

 inch to a whole one in diameter. 



Polygyra mullani^ Bland, Mullan's Snail, was at 

 one time considered as a small variety of the last 

 species, but it is now believed to be distinct. The 

 shell is shining, with a thin epidermis covered with 

 minute spiral lines and tubercles. The aperture is 



