Page:Land Mollusca of North America (north of Mexico) Vol. I Part 1 277-end.pdf/18

 smallest, 12.5 x 23.2 mm.; very few are under 25 mm. diameter. The largest shell in the lot from the west side of Hog Canyon measures 17.5 x 30 mm. A strongly depressed shell measures 15.3 x 29 mm.

The Tortillitas are a short range about ten miles northwest of the Santa Catalinas. They are arid mountains without forest.

Sonorella sabinoensis Pilsbry & Ferriss Fig. 164 a-e'.

Sonorella sabinoensis Pilsbry & Ferriss, 1919, Proc. Acad. Nat., Sci. Phila., for 1918, 70: 289, pl. 4. figs. l-5d; text-fig. 3.

The shell is rather narrowly umbilicate, width of umbilicus contained nearly 8 times in that of shell in the type specimen, rather solid; cinnamon- buff, broadly zoned with white (or whitish) on both sides of the chestnut- brown band above the periphery. The surface is glossy; embryonic whorls when unworn with a smooth tip, followed by radial wrinkles and some granulation, then spirally descending threads with radially corrugated intervals, and with some interrupted ascending spirals near the upper suture. Subsequent whorls delicately marked with growth-lines. Suture descends moderately in front. The aperture is large, oblique, rotund-oval. Peristome narrowly expanded, dilated at the umbilical insertion.

Height 12.7 mm., diameter 21.3 mm.; aperture 12 x 13 mm.; 4-1/4 whorls.

Genitalia (Fig. 165 a, b) resembling those organs in S. marmorarius. The penis is thin, not swollen basally. The verge is slender and corrugated, as in the other species, and nearly as long as the penis (Fig. 165 a). The flagellum is either minute or wanting. Five measure:

Penis Verge Epiphallus Flagellum Vagina Diam. shell

10 7 8 0 9 21.3, type

9.5 8 7 0 7.3 22.8

10.5 10 9 -1 9 26.7

9 7 6 0.3 8.5 24.0

8.5 8 6.5 0.5 6.5 23.2

Arizona: Santa Catalina Mountains in Sabino Canyon (Ferriss), Type 109097, Station 16, 1913, and its tributaries, Sycamore Canyon and Mt. Lemon Fork, from about 3000 to 6000 feet elevation. Also Rock and Vantana canyons, west of Sabino, and Bear Canyon eastward.

It is a species of the dry, sun-baked rock-slides, living ones found only deep in the crevices, in the lower levels with desert vegetation. The Sabino Basin, Sycamore and Bear Canyon localities are below the pine belt, in arid country, with some oak, juniper and sycamore. The species is not known to occur in the humid upper forest.

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