72 



PROCEEDINGS OP THE ACADEMY OF 



[Feb., 



Measurements of the genitalia in millimeters. 



Species. 



1. 

 2. 

 3. 

 4. 

 5. 

 6. 

 7. 

 8. 

 9. 



S. virilis 



it 



It 



it 

 It 

 It 



S. r. leucura 



it 



a 



CL, 



o 

 S 



3 

 

 x 



3 

 S 



29 



30.5 



34 



30 



27 



28 



31 



2S.5 



0.7 

 1 



0.6 

 0.6 

 0.6 



23 



26.5 

 16 

 19.5 



31 

 24 





17 

 21 

 15 



26 



25 



94.335 

 94,332 

 79,622 

 97,409 

 97,409 

 97,408 

 94,331 

 99,682 

 99,681 



The specimens measured are from the following localities: 



1. South Fork of Cave Creek. 



2. Foot of Reed's Mountain, Cave Creek. 



3. Rucker Canyon (?). Original type of S. virilis. 



4. 5. Head of Rucker Canyon. 



6. Rucker Canyon at mouth of Raspberry Gulch. 



7. White Tail Canyon, Station 4. 



8. White Tail Canyon, Station 14. 



9. White Tail Canyon, Station 00. 



Sonorella virilis leucura subsp. nov. PI. II, figs. 7-9. 



The shell is decidedly more depressed than S. virilis or S. v. "circum- 

 striata," though the spire is about equally convex; the umbilicus is 

 wider; the aperture is smaller, and the ground-color is paler, sub- 

 opaque, whitish, tinted more or less with brown, nearly white on each 

 side of the dark band, and pale around the umbilicus. 



Embryonic and neanic stages. — There are If embryonic whorls. 

 The depressed tip is smoothish, followed by only a few radial wrinkles; 

 following embryonic whorl is roughened with low granules lengthened 

 in a radial direction, or short, irregularly waved or vermiculate radial 

 wrinkles ; over these there is a pattern of grains in regular squares at 

 first, but soon forming protractive rows, the grains becoming indis- 

 tinct. On the first post-nepionic whorl the fine striae are more or less 

 interrupted or minutely indented in places. The post-nepionic whorls 

 as far as the fourth whorl are clothed with very short deciduous hairs, 

 so delicate that the slightest attempt to clean the shell removes them, 



