

1918.] NATURAL SCIENCES OF PHILADELPHIA. 299 



24. Southern slope of mountains at eastern gate of John Rhodes' ranch, among 

 boulders on mesa. 



26. Rhodes' canyon. 



27. Northern slope, amphitheatre on Whitlock ranch. 



28. Foot of main gulch facing north, same amphitheatre. 



29. Farther up same gulch. 



30. "Porphyry" slide on trail IJ miles south of Copper Creek Mining Camp. 



Type locality. 



31. Camp at smelter, Copper Creek. 



32. Rock slide sloping west, on trail half way between Copper Creek Camp and 



Table Mountain. 



33. "Porphyry" slide in forks of creek 2 miles east of Table Mountain. 



34. Slide near the preceding. 



3.5. Cliffs on northeastern slope of Table Mountain. 



Genitalia (fig. 7). The general proportions are as in S. marmoT' 

 arius. The penis has a long, ver\' thin sheath about the basal part, 

 not seen in mannorarius; its lower portion is somewhat swollen and 

 has several small longitudinal folds within. Retractor muscle long. 

 Papilla weakly annulate, about half as long as the penis. There is 

 the usual short flagellum. The vagina about equals the penis in 

 length. 



Length of penis 10 mm. 



papilla 5 



epiphallus .... 7 



flagellum 1.5 " 



vagina 9 " 



Museum No 118,122. 



This form is much like S. marmorariiis. The shell is slightly more 

 capacious and darker colored, and there is some difference in the penis. 

 Its habitat is separated from that of marmorarius by the valley of 

 the San Pedro River. The elevation is much less than that in- 

 habited by *S. marmorarius. 



20 living specimens from Station 30, all taken, measure as fol- 

 lows: 



Diameters in mm. . . 25 25.5 26 26.5 27 27.5 28 29 

 No. specimens ... (1) (1) (2) (2) (3) (2) (8) (1) 



17 specimens from Station 24, a southern slope; 



Diameters 24 24.5 25 26 26.5 27 28 28.5 30.5 



No. specimens.... (1) (2) (3) (2) (4) (1) (2) (1) (1) 



Sonorella tortillita n. sp. PI. V, figs. 4, 4a, 46. 



The shell is umbilicate (width of umbilicus contained about 8f 

 times in that of the shell), pinkish buff, fading to white around the 

 umbilicus and paler near the chestnut-brown band which revolves 

 above the periphery of the last whorl and shows very narrowly above 

 the suture on most of the penult whorl. The surface is glossy; 



