1918.] NATURAL SCIENCES OF PHILADELPHIA. 311 



canyon streams live the mountain trout, friendly and well condi- 

 tioned, but they are not the cut-throat trout of the Colorado. 



On the whole the Mogollons, in scenery and camping delights, are 

 not far behind the White and Blue Mountain region of eastern Ari- 

 zona. Silver City is the nearest and most convenient railway 

 station, and moreover it lies in a region unexplored by the snail 

 fraternity. 



One more killing was made on the return to Clifton, a colony of 

 Sonorellas at Steeple Rock, Sept. 14. Thus this event of 1914 had a 

 continuous run of two months and seven days. 



Aside from the minute Canadian Zone snails which have a wide 

 distribution at high levels, and the minutiae of the desert foothills 

 such as ThysanopJiora hornii, Succinea avara, the small Zonitoides, etc., 

 there are several forms showing close affinity between the San Fran- 

 cisco-Mogollon region and the Chiricahua Range. The species 

 Sonorella binneyi, Ashmunella chiricahuana and Orohelix barbata of 

 the Chiricahuas are represented here by S. binneyi franciscana, A. 

 mogollonensis and 0. barbata. The toothed Ashmunellas are of 

 nearly related species, and the same group of forms extends farther 

 east in New Mexico to the Black Range. None of the species 

 mentioned are found in the northern or Dos Cabezas part of the 

 Chiricahua range, their habitats being from 80 to over 100 miles 

 south of the regions now under consideration. The intervening 

 region is at the present time too dry for the existence of these snails. 



HELICID-^. 



Sonorella grahamensis n. sp. PI. VI, figs. 7, 7a, 7h. 



The shell is umbilicate (the width of umbilicus contained about 8^ 

 times in the diameter of shell), very thin, tawny-olive, paler at the 

 base, with the usual band; not very glossy; under the lens showing 

 the usual weak growth-lines, and both above and below there are 

 numerous spiral impressed lines. Whorls slowly increasing at first, 

 the last rapidly widening, descending in front. Aperture rounded- 

 oval, quite oblique. Peristome is thin, very Httle expanded. 



Alt. 10, diam. 19 mm.; umbihcus 2.2 mm.; 4^ whorls. 



Genitalia (fig. 9). The penis has a well developed sheath at the 

 base, and contains a long, tapering papilla. The penial retractor 

 is inserted at the base of epiphallus and apex of penis as in the 

 hachitana group. There is a short flagellum. The organs measure: 



Length of penis 9 mm.; papilla 7; epiphallus 6; flagellum 0.5; penial 

 retractor 4.7; vagina 7; spermatheca and duct 19 mm. 



