284 PROCEEDINGS OF THE ACADEMY OF [Mch., 



the middle of the upper surface and another immediately below the 

 white keel, the early whorls dull brown; without perceptible cuticle. 

 Sculpture of close but irregular and rather shar]) growth-wrinkles, very 

 indistinctly decussated with s]oiral strife. The embryonic shell consists 

 of only H whorls. The first half whorl is nearly smooth, the next 

 whorl is sharply and finely but very regulorly ribbed radicdly. With the 

 compound microscope some veiy weak spiral striation may Idc seen in- 

 distinctly in the intervals. At the end of the embryonic period the 

 rib sculpture abruptly gives place to a lower, less regular oblique 

 striation. The spire is convexly conic. Wliorls 5, convex, impressed 

 above the sutiu-e, where the keel projects a trifle. At the periphery 

 the keel projects somewhat, the siu-face being a little concave above and 

 below it. Base convex. Aperture small, oblique, a little angular at 

 the outer part. Lip simple, the ends approaching. 



Alt. 6.5, diam. 11 mm. 

 " 7, " 10.5 " 



Cave Creek Canyon, Chirieahua Mountains. Types No. 87,012, 

 A. N. S. P., collected by James H. Ferriss. "Occurred on a dry, clay 

 hillside, under dead vegetation and stones, and was found nowhere 

 else on the mountain." 



This is a very distinct little species, closely related to 0. avalonensis 

 Hemphill of Santa Catalina Island, California, which has an apex of 

 the same type. 0. avalonensis differs, however, b}^ its conspicuously 

 decussate surface, wider last whorl and larger aperture, and it has a 

 half whorl less. It is figured for comparison, PI. XI, figs. 4, 5, 6, 7. 

 The umbilicus is about equal in the two species. 



0. chiricahuana differs conspicuously from 0. yavapai and 0. y. 

 neomexicana by its peculiar apical sculpture, etc. 



The genitalia are figured (PL XIX, fig. 4). The penis is cylindric, a 

 little flattened and protruding on one side at the distal end. The epi- 

 phallus is longer than the penis, club-shaped, the retractor inserted 

 upon it not far from its base. The lower part of the spermatheca duct 

 is enlarged and muscular. The lengths of the organs are as follows: 

 penis 4, epiphallus 4.7, vagina 3.5, spermatheca and duct 7.5 mm. The 

 foot is scarcely granulose, the integument smoothish, tessellated in 

 rather coarse pattern with blackish or gray spots. No genital furrow 

 is visible. The mantle edge is thin. 



The jaw (PI. XXIII, fig. 24) is striate, somewhat less arcuate than 

 that of 0. clappi. 



The radula (PI. XXII, figs. 10, 11) has 26.1.26 teeth. They are 

 rather shorter than usual in Oreohelix. The central and lateral teeth 



