414 PROCEEDINGS OF THE ACADEMY OF [Juue, 



Station 22. Low crags in the northern part of Oro Fino Canyon. 



Station 23. Crags on the southern rim of the northern branch of 

 Thomas Canyon. 



Station 24. West side of the main ridge near summit, south of 

 Baboquivari Peak. Vitrea indentaia umbilicata and Sonorella 

 vespertina. 



Station 25. East side of ridge, about' half a mile from the peak. 



Station 26. Near the southwestern head of Sycamore Canyon, 

 l^etween one and two hundred yards below the summit of the Thomas- 

 Sycamore ridge, in a rock "sUde." 



Station 27. About 1,000 feet below Station 26, near the bottom 

 of the canyon. 



Station 28. Not far below Station 27. 



Station 29. Bed of upper Sycamore Canj^on, about a mile above 

 the foresters' cabin, and not far above the clam. 



Station 30. Creek in Sycamore Canyon (a small Physa, not 

 determined with certainty, was the only fresh-water shell found at 

 this station). 



Station 31. Sycamore Canyon, about 3 miles up its bed, and 

 f mile up a southwestern branch ravine. Succinea avara Say and 

 Sonorella baboquivariensis only. 



Sonorella vespertina n- sp. PI. X, figs. 5. 5a, 56. 



The shell is uml^ilicate (width of umbilicus contained 9 or 10 

 times in diameter of the shell) ; cinnamon, fading to whitish around 

 the umbilicus, and with white bands above and below the chestnut- 

 brown shoulder band. Surface glossy, the initial half-whorl having 

 some radial wrinkles, the rest of the embryonic shell without any 

 ■distinct sculpture, though there is some extremely indistinct radial 

 roughness, stronger near the suture. In fresh young shells of 2| 

 whorls the surface of the last embryonic and first neanic whorls 

 is densely set with very short hairs, extending also over the base. 

 These are fugacious, lost with further growth. The later whorls 

 are marked with the usual growth lines. Whorls 4|, the last rapidly 

 widening, rather steeply descending close to the aperture. Peristome 

 narrowly expanded on the outer and basal margins, dilated and 

 reflexed at the columellar insertion. 



Height 11, cUam. 19.8 mm. (tvpe). 

 " 11.3, " 20 " 



10, " 18 " 4i whorls. 



Genitalia (PI. XIII, fig. 9). — The penis is very small and tapers 

 distally to the epiphallus, the long penial retractor being inserted 

 on the latter. The flagellum (fl.) is represented by a minute bud or a 

 slight swelling. The penis-papilla (fig. 9, pp.) is slender, tapering, 



