92 PROCEEDINGS OF THE ACADEMY OF [Vol. LXXV 
on anatomical structure. The shells are greatly varied in size and 
form, and two species S. dalli and S. parva, possess rudimentary 
“teeth.” We here figure a specimen of 
the former having these teeth well de- 
veloped (Text-fig. 10). 
Besides these species, there are two 
others not yet dissected. S. hwachucana 
was taken in 1904. It was originally 
described as a subspecies of the Chirica- 
huan S. virilis. Somewhat faded bones 
Fig. 10.—Sonorella dalli of another species of about 20 mm. diam- 
showing parietal teeth. —_ ter, with smooth (not granulose) surface 
was taken in 1919 at Station 270, at the northern end of the range. 
As it belongs to a group of very weakly differentiated species, 
we do not attempt to name these specimens, which certainly differ 
specifically from any described Huachucan species. 
Key to Huachucan Sonorellas by Characters of the Genitalia. 
a. Penis long (about 40 mm. in a shell 27 mm. diam.), containing 
a short papilla (about 4 length of penis); epiphallus long 
(49-60 mm.); flagellum present. S. dalli Bartsch. 
a’. Penis long (about 20-25 mm. in a shell of about 16 mm. diam.), 
containing a long, longitudinally costulate papilla; epi- 
phallus shorter than penis; no flagellum. S. parva Pils. 
a, Penis shorter, about equalling the diameter of shell or much 
less, containing a thick, cylindric papilla. 
b. Papilla less than half the length of penis; vagina shorter than 
penis; epiphallus thickened where it passes into penis. 
S. sitiens montezuma P. & F. 
6’. Papilla more than half the length of penis; epiphallus not 
enlarging where it enters penis; vagina much longer than 
the penis. 
c. Upper part of vagina muscular, swollen, usually fusiform; 
penis 5 to 7.5 mm., papilla 3.3 to 5 mm. long. 
S. granulatissima Pils. 
c', Vagina rather slender throughout, with a small fleshy node 
midway or at the upper third; penis 12 to 19 mm., papilla 
9 to 138 mm. long. S. danielsi P. & F. 
Sonorella danielsi P. & F. 
This is a common shell in Ash canyon, Stations 310, 311, 330 
(1919), Montezuma and Copper canyons, no. 314, 316, 318-320, 
322-324, 327-329, all 1919. Its known range is thus extended 
considerably. 
