AIR-BREATHING SNAILS AND SLUGS 265 



tened above, at the aperture, as is shown in the figure. 

 A dark colored variety is found in Alaska. As the 

 name indicates, this species makes its home about 

 Puget Sound, but it also extends down to California, 

 and eastward to Idaho and Montana. The var. 

 keepi^ Hemphill, is a perfect miniature of the type, 

 and is reckoned as an extremely small variety of 

 the same. It is sparingly found in the Contra Costa 

 hills, back of the city of Oakland. 



Selenites sportella^ Gld., the Sportive Selen, is 

 decidedly smaller than the normal form of the last 

 species. Its color and shape are similar, but it is 

 marked by sharp growth-striae. The difference is 

 most plainly seen on the base of the shell, which in 

 the last species is smooth, while in this it is decidedly 

 striated. This species lives near the coast, all along 

 our western border. 



Figure 262 shows us a basal view of Se- 

 lenites voyana^ Newc, Voy's Selen, (M^- 

 crocycUs voyana). Notice the wide um- 

 bilicus and the triangular aperture. The 

 shell is thin, translucent, very light horn- 

 colored, and has fine lines of growth. This species 

 lives along the California coast. 



Selenites he?nphilli, W. G. Binney, Hemphill's 

 Selen, is a small species, half an inch across, thin, 

 glossy, marked by irregularly impressed lines of 

 growth, without any trace of revolving lines. This 

 shell is also known as Circinaria hempliilU. Its home 

 is in Oregon. 



Selenites duranti, Newc, Durant's Selen, is a lit- 

 tle affair, only 4 mm. across, widely umbilicated. 



