PUPILLA, AMERICAN. 167 



in oblique view in the aperture a columellar tubercle may be 

 seen. It differs from P. syngenes by the absence of a crest 

 behind the lip, though there is a wide, shallow contraction 

 there. 



Length 4.2, diam. 1.75 mm., 7y 3 whorls. Spud Rock. 



Length 3.65, diam. 1.9 mm., 7 whorls. S. Catalina Mts. 



Length 3.2, diam. 1.85 mm., 6y 2 whorls. S. Catalina Mts. 



Arizona: Santa Catalina Mountains, Pima Co., abundant, 

 generally distributed from 8000 to 9500 ft. ; Spud Kock, Bin- 

 con Mts. ; Chiricahua Mts., Cochise Co., at the head of Cove 

 Creek, 8000 ft., and Pine Canyon, 7500 ft., type loc. (Ferriss). 



Pupilla hebes form nefas Pils. & Ferr., Proc. A. N. S. Phila., 

 1910, p. 135. P. h. nefas PILS. & FERR., op. cit., 1918, p. 303. 



In the Chiricahuas this race was not found associated with 

 the dextral hebes, which was taken in Rucker canyon. In 

 the Santa Catalina and Rincou mountains it was found at 11 

 stations, often in large numbers, but in only one place, near 

 Marshall Pass, were hebes and nefas found together. 



This sinistral race evidently appeared as a mutation some- 

 where in southeastern Arizona, and as yet has spread over 

 only a few ranges of that region. Nothing has been seen of 

 it in the extensive regions north and northwest, inhabited by 

 dextral hebes. 



6. PUPILLA SYNGENES (Pilsbry). PI. 18, figs. 9, 10, 11. 



The shell is sinistral, cylindrical but somewhat wider above, 

 blunt at each end ; cinnamon brown, or somewhat darker. 

 Surface dull when fresh, delicately obliquely striate. Apex 

 large, obtuse ; suture impressed ; whorls 8, the last one com- 

 pressed and flattened around the lower-outer portion, its last 

 third ascending on the next earlier whorl, and elevated into 

 a high rounded ridge or crest a short distance behind the 

 outer lip. Aperture slightly oblique, truncate-oval in form; 

 the outer lip narrowly expanded, basal and columellar mar- 

 gins broader ; about the middle of the parietal wall, or nearer 

 the upper end, there is a small parietal lamella about one- 

 fourth of a whorl long. Far within there may be seen a blunt 

 columellar lamella; and most specimens exhibit far within 

 the outer lip a tubercular lower-palatal fold. 



