1918. 



NATURAL SCIENCES OF PHILADELPHIA. 



295 



Alt. 14 diam. 25 mm.; aperture 11.2x13.6 mm.; 4f whorls. 



Marble Peak, Santa Catalina Mountains, Arizona; type loc. 

 Station 26, 1913, quartzite slide on Marble Peak. Also found at 

 Station 3, 1911, slide above Apache mine; Station 4, 1911, top of 

 ridge south of the Peak; Station 38, 1913, north side of Marble 

 Peak; ''Joliet Cave," and other stations on the same mountain. 



Fig. 6. Genitalia of Sonorella marmorarins, a, No. 109,077; h, c, No. 109,071; 

 d, No. 109,0.39; e, No. 109,083;/, No. 109,084; g, No. 109,078. 



Genitalia (Fig. 6a-g). The penis is thin-walled, very weakly or 

 usually not noticeably enlarged near the atrium, containing a slender 

 tapering, corrugated papilla, half to two-thirds or more the length 

 of penis. Epiphallus somewhat shorter than penis, typically ter- 

 minating in a little flagellum, but this is often rudimentary or wanting. 

 Penial retractor long, inserted on apex of penis and base of epiphallus. 

 The vagina is but little shorter than the penis. Lengths of the 

 organs in mm. follow, the specimens all from stations on Marble 

 Peak: 



