1910.J 



NATURAL SCIENCES OF PHILADELPHIA. 



75 



Fig. 6. — Collecting stations in White Tail Canyon. 



rest of the embryonic shell has irregular rugosities or asperities, short, 

 but longest in a radial direction ; over these there are granules arranged 

 as in S. v. leucura. When absolutely unworn they bear delicate hairs 

 in young shells. The following post-embryonic whorls are delicately 

 striate, and as far as the beginning of the fourth whorl, fresh and 

 uncleaned young shells have close, short and very delicate hairs. The 

 last whorl has delicate growth-lines, but no trace of spiral stria?; it is 

 rounded at the periphery and descends a little in front. The aperture 

 is oblique, rounded. The peristome is thin, outer margin scarcely 



