80 PROCEEDINGS OF THE ACADEMY OF [Feb., 



piriform, the lip margins converging, thickened at the ends and 

 connected by a thin film across the parietal wall. Interior bluish 

 white. Alt. 9, diam. 16 mm., whorls 5. 



Big Emigrant Mountain, on the south side of Big Emigrant Canyon, 

 at about 7,000 feet elevation, taken in some numbers in a shattered 

 column of stone and also in a rock slide. This place is about 20 miles 

 across the mountains northwest from the Cave Creek Station for 

 O. clappi. 



O. c. emigrans is the dirtiest of the group — in its natural state as 

 black as the soil. It is well distinguished by the sculpture, and would 

 be considered a separate species in a less variable group than Oreohelix. 



Oreohelix clappi Ferriss. 



Oreohelix clappi Ferriss, Nautilus, XVIII, p. 53 (Sept., 1904). Pilsbry, 

 Proc. A. X. S. Pliila., 1905, p. 285. pi. 25, figs. 54-56 (shell); pi. 19, fig. 8 

 (genitalia); pi. 22, fig. 4 (teeth); pi. 23, fig. 26 (jaw). 



The shell is moderately depressed, with tubular whorls and deep 

 suture, the altitude about two-thirds t he diameter and about equally con- 

 vex above and 1 >el< >w the peripheral angle. The umbilicus at the opening 

 is about one-sixth the diameter and contracts rapidly, only the penul- 

 timate whorl visible. Calcareous layer of the shell is brownish white 

 under a thin greenish-yellow cuticle with some darker oblique streaks, 

 which become in mature shells darker and crowded near the aperture. 

 Many possess two indistinct transparent olive spiral bands, one above, 

 the other just below the periphery. In old individuals the cuticle 

 remains only in ragged shreds. The first \\ embryonic whorls are 

 strongly ribbed radially; these riblets are regular and narrower than 

 their intervals. At the end of the embryonic shell the whorl slightly 

 widens abruptly, with sculpture of rather coarse irregular obliquely 

 radial wrinkles and traces of fine spiral striae. The last whorl has 

 unequal, irregularly spaced oblique wrinkles, iccak and loic at the base, 

 which is densely covered with minute wavy spiral stria?, obsolete in old 

 individuals. Where the wrinkles pass over the angular periphery they 

 are sometimes somewhat more emphatic, a little pinched up. There 

 are no spaced circular threads or cuticular fringes on the base. Whorls 

 4f, convex, the last double the width of the preceding. Base very 

 convex. The aperture is very shortly ovate or nearly circular, very 

 oblique, and about one-half the diameter of the shell. The ends of the 

 lips converge. The short parietal callus is a thin transparent film, or 

 in old shells the peristome is continuous, as a raised parietal ledge. 

 Old age is expressed by a deeper descent of the last whorl and closer 

 approach of the lip margins, as usual in the genus Oreohelix. 



