1915.] NATURAL SCIENCES OF PHILADELPHIA. 369 



Height 7, diam. 14.2 mm.; 4| whorls. 



Genitalia (Plate XI, figs. 3, 3a). — The penis is somewhat slender, 

 slightly shorter than the vagina, and a trifle longer than the epi- 

 phallus. It contains a cylindric papilla nearly as long as itself, trans- 

 versely wrinkled in the distal third and rounded at the end (fig. 3a). 

 The retractor muscle is inserted on the epiphallus near its base. 

 There is no flagellum. Length of penis 4 mm.; penis-papilla 3 + 

 mm.; penial retractor 6 mm.; epiphallus 3+ mm.; vagina 5i mm. 



Dragoon Mountains, from the northern ridge of Tweed Canyon 

 to the ridges facing the northern slope of the mountains; types 

 No. 103,097, A. N. S. P., from Station 38. Also taken at Stations 

 3, 4, 5, 10, 12, 13, 14, 15, 21, 22, 38-41. 



The shell in this extremely distinct species reminds one a little 

 of Trichodiscina. There is no other Sonorella like it. The embryonic 

 sculpture is a modification of the hachitana pattern. In the genitalia 

 it resembles S. bicipitis of the Dos Cabezas range as much as any- 

 thing. It is abundant in the northern part of the Dragoon Range, 

 but Tweed Canj^on apparently forms an impassable barrier to its 

 spread southward. 



We rarely found Sonorella ferrissi sealed to stones, forming small 

 rings. Most living ones were seen loose under stones or in the 

 earth, lying with the ap-erture up, like Eastern Helices, and sealed 

 with a somewhat convex white epiphragm. It belongs exclusively 

 to the limestone terrain. 



Sonorella dragoonensis n. sp. PI. VIII, figs. 1, la, lb. 



The shell is rather depressed, umbilicate (the umbilicus contained 

 6^ times in diameter of the shell), thin, somewhat translucent, pale 

 buffy brown, with whitish bands on both sides of a chestnut-brown 

 band at the shoulder. The spire is low, conic, whorls 4f , moderately 

 convex. First one-third whorl smooth, followed by a brief stage 

 of coarse radial wrinkles, continuing longest near the lower suture, 

 and succeeded by papillae and short, vermiculate radial wrinkles, 

 interrupted by short wrinkles in a spiral direction, which on the 

 lower part of the whorl bear epidermal bristles, beginning on the 

 latter half of the first whorl, and continuing throughout the embrj^onic 

 and neanic stages as far as the end of the third whorl. It is suc- 

 ceeded by an excessively minute vermiculate sculpture, which 

 rapidly becomes fainter and disappears on the last two whorls, 

 which are glossy and nearly smooth except for faint growth lines. 

 Last whorl wide, descending in front. Aperture very oblique, 



round-oval. Peristome thin, very narrowly expanded throughout, 

 24 



