398 PROCEEDINGS OF THE ACADEMY OF [Jime, 



Walnut branch of Agua Caliente; and Stations 17 and 17|, Camperel 

 Canyon, on the eastern slope of the mountains, at about 6,500 feet. 



This is a smaller, thinner shell than other Santa Rita Sonorellas, 

 and readily distinguished by its microscopic granulation and the 

 beautiful sculpture of the embryo. It is variable in degree of eleva- 

 tion of the spire, size of umljilicus and color. In Madera Canyon 

 the shell has a russet hue. 



In Walnut Branch of Agua Caliente the color ranges from almost 

 chamois in the thicker old individuals to nearly water green in those 

 barely grown to full size. The microscopic granulation is sometimes 

 typically developed on the last whorl, but more often more or less 

 obsolete, sometimes only visible in a few places; and most specimens 

 show incised spiral lines on the last whorl, occasionally quite distinct 

 and numerous. Around the head of Agua Caliente Canyon the color 

 is similar to the Walnut Branch lot. 



S. clappi resembles the Huachucan S. granulatissima and S. 

 danielsi in the embryonic sculpture and the general appearance, but 

 in those species the aperture is more oblique than usual in S. clappi 

 and the genitalia are conspicuously different. Having dissected a 

 good many individuals of all of these species, I feel confident that 

 the genitalia afford the most reliable specific characters. S. dapyi 

 is very much like *S. walkeri in genitalia. 



A couple of shells from Station 17^, Camperel Canj^on, on the 

 eastern slope of the range, resemble the Agua Caliente form in being 

 light colored. One from Station 17, in the same canyon, is the 

 darkest of all, being nearly a sorghum-brown color, more vinaceous 

 where the cuticle is worn off. The genitalia (PI. XII, figs. 4, 4a) 

 differ from typical S. clappi by the longer penis and penis sheath, 

 and the shorter vagina. Length of penis 13, penis-papilla 10, epi- 

 phallus 10, flagellum 1, vagina 4^ mm. 



A bleached Sonorella, No. 105,385, U. S. N. M., collected, or at 

 least sent to Dr. I. Lea in 1860, by H. C. Grovenor, is labelled "Santa 

 Rita Mountains, 6,000 feet above the sea." It is very thin and 

 appears under the lens to have been granular. The lip-ends con- 

 verge, as in S. clappi, from which this shell differs by its larger size 

 and less depressed shape; diam. 20.5 mm. It is probably a distinct 

 species related to S. clappi, but it is not in condition for description. 

 The spire is broken. 

 Sonorella granulatissima occidentalis a. subsp. PI. IX, figs. 7, 7a, 7b. 



Similar in sculpture to *S. granulatissima, but differing by the 

 narrower last whorl, which is less convex above; the light borders of 

 the chestnut-brown band, and the less depressed spire. 



