Page:Land Mollusca of North America (north of Mexico) Vol. I Part 1 277-end.pdf/3



around the umbilical region. The dark band runs about 2-1/2 whorls up the spire. Whorls 4-3/4, the last rather deeply descending in front. Aperture rounded-oval, the peristome thin, expanded, the dilated columellar end partially covering the umbilicus.

Height 12.7 mm., diameter 20.8 mm., alt. aperture 10 mm., width 11.7 mm.; width of umbilicus 2.4 mm.

Arizona: Brown Canyon,1 Huachuca Mountains (J. H. Ferriss), Type 89225 A.N.S.P. Hill southeast of cave, Manila mine district, northwest foothills; also Patagonia mountains.

This species was collected by Mr. Ferriss in the course of a rapid trip in the winter of 1903-4; no soft parts were preserved. It was described as a subspecies of S. virilis on account of its faint spiral lines, but that Chiricahuan snail differs by its far more depressed and more widely umbilicate shell. On studying the type anew it appears that the shell is not distinguishable from that which was described later as S. patagonica. The latter is evidently a synonym. I am leaving as subspecies the local forms aquacalientensis, mustang and cotis. All seem closely related, and perhaps the recognition of local races was not required, though each is isolated by desert tracts.

The species as now understood contains rather capacious shells with small umbilicus, contained from nearly 7 to more than 8 times in the diameter, and often showing some impressed spiral lines on the upper part of the last whorl. The small, slender penis is somewhat enlarged anteriorly, and the anterior part of the vas deferens is noticeably enlarged, as in S. walkeri, often thicker than the epiphallus. It probably lives in a lower zone than other Huachucan species, and thus has been overlooked in most visits to that range.

In Bear Canyon, Huachuca Mountains, Mr. Ferriss found a few specimens somewhat similar to those from Brown Canyon, but noticeably more depressed, with a smaller mouth and obtuse lip. One measures, height 11.6, diameter 20.3, aperture 9.7 x 11 mm., umbilicus contained 7 times in the diameter. The shell is somewhat more solid, and the spiral lines are more distinct. In both forms they may be seen with a hand lens (Proc. Acad. Nat, Sci. Phila., 1909. pl. 19, fig. 16).

As this species seems to be most copiously developed in the Patagonia Mountains (whence it was described as S. patagonica), a further description of those shells follows.

The shell is rather capacious with umbilicus contained 8 times in the diameter; glossy, dilute pinkish-buff, fading to white or whitish on the base and in a broad band below, a narrower one above the chestnut-brown band above the periphery. Embryonic sculpture on the first half whorl of radial ripples, then becoming areolate, the second whorl with forwardly descending

1 This is a short canyon between Tanner and Ramsey canyons, represented but not named on the Topographic Sheet, Hereford Quadrangle (1914).

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