1918.] 



NATURAL SCIENCES OF PHILADELPHIA. 



291 



Sonorella sabinoensis occidentalis n. subsp. PI. V, figs. 1 to 16. 



The shell appears indistinguishable from *S. sabinoensis. 

 Alt. 16, diam. 28 mm.; 5 whorls. 



This form is separated from S. sabinoensis solely on account of 

 the difference in the penis, which is enlarged at the base in occi- 

 dentalis, slender in sabinoensis. While the Pima canyon shells are 

 distinguishable from the large-mouthed typical forms of sabinoeiisis, 

 we can find no difference in the sabinoensis with slightly smaller 

 aperture, such as those from Sabino canyon Station 9 (which agree 

 in genitalia with the type of sabinoensis). No specimens with the 

 penis swollen basally were found among the numerous Sabino canyon 

 individuals opened. 



The head and back are hair brown, fading to drab on the sides, 

 the tail and entire sole being dull chamois to dull cream-buff. 



Western end of the Santa Catalinas; type No. 119,491, from Sta- 

 tion 36, east side of Pima canyon. Also on the west side, Station 

 37 (Pusch Ridge); Station 43 (1917), northeast of Sutherland's 

 ranch, in the foothills; Station 45, in the large canyon north ^of 

 Romero canyon (eastward from Sutherland's). 



Fig. 4. Genitalia of *S. s. occidentalis. a, No. 118,052. b, No. 118,045, with detail 

 of penis and papilla at c; d, No. 118,056, canyon north of Romero Canyon. 



