1909.] NATURAL SCIENCES OF PHILADELPHIA. 517 



A NEW SONORELLA FROM THE RINCON MOUNTAINS ARIZONA. 

 BY H. A. PILSBRY and J. H. FERRISS. 



The Rincon Mountains lie near the western border of Cochise County, 

 Arizona, north of the Whetstone Mountains, which are north of the 

 Huachuca range. 



In 1907 one of us (Mr. Ferriss) visited the range and procured 

 specimens of a large Sonorella, the first mollusk known from these 

 mountains. 



Fig. 1. Sonorella rinconensis. Cotypes, nat. size. 



Where visited the range is rather dry. The rock is granitic, of 

 pre-Cambrian age. l Besides Sonorella rinconensis onty a few shells 

 were taken, minute forms common to the region. Sonorella rincon- 

 ensis was found sticking to large rocks and boulders, a habit not 

 hitherto noticed in the genus. They are rare, the biggest bag made 

 being six in one day. 

 Sonorella rinconensis n. sp. PI. XXII, figs. 1-4, 7. 



The shell resembles S. ashmuni Bartsch in shape. It is pale brown 

 fading to white around the umbilicus, with a broad chocolate shoulder- 

 band, widely whitish-bordered above and below. The surface is 

 smoothish, marked with delicate growth-lines, and under the lens some 

 faint spiral lines may be traced on the last whorl near the suture. The 

 embryonic whorls have sculpture of the S. hachitana type. The 

 whorls increase rather slowly to the last, which is much widened, and 

 well rounded peripherally. It descends a little in front. The aper- 

 ture is rotund-lunate; peristome slightly expanded, dilated at the 

 columella as usual. Umbilicus about as in S. ashmuni. 



Alt. 16, diam. 26.5, width of umbilicus 4 mm.; whorls fully 5. 



The penis is extremely long and slender, and contains a very long 

 papilla. Its lower end is enveloped in a sheath. The retractor 



1 Cf. W. P. Blake, Some Salient Features in the Geology of Arizona, with 

 Evidences of Shallow Seas in Paleozoic Time, American Geologist, Vol. 27, 1901 

 p. 160. 



