Page:Land Mollusca of North America (north of Mexico) Vol. I Part 1 277-end.pdf/8



whorl has minute, irregular, radial wrinkles partly anastomosing on the first half whorl, then very fine, forwardly-descending threads over them, about as in S. hachitana.

Height 15.3 mm., diameter 26.5 mm.; barely 5 whorls. Station 332. Type.

Height 15.5 mm., diameter 25.7 mm.; 5 whorls. Station 153.

Height 13 mm., diameter 25 mm.; 4$ whorls. Station 153.

Genitalia (Fig. 151: 5) of the hachitana type, but characterized by the much greater length of all of the male organs, which are decidedly longer than in S. h. flora, which has a shell at least as large as S. mustang. The penis is slender, having a sheath which is thick and muscular near the base. Its verge is about two-thirds the length of penis, tapering and slender. The flagellum is unusually long; beyond the flagellum the vas deferens is somewhat enlarged, as in the related forms. The lengths of the organs are as follows: penis 15.5 mm., penial retractor 11.5 mm., verge 10.5 mm., epiphallus 8.0 mm., flagellum 2.0 mm., vagina 13.5 mm., A.N.S.P No. 44048. Station 286.

The jaw has 6 strong ribs.

Arizona: Mustang Mountains, Santa Cruz County (J. H. Ferriss), Type 130992 A.N.S.P.

While not conspicuously unlike S. huachucana, the differences are constant in a large number of shells compared. It appears to be distinct from cotis anatomically, by the longer penis, which is about three times as long as in S. cotis, while the epiphallus is about equal. The umbilicus is wider than in cotis, patagonica or huachucana. S. h. mustang seems better characterized than the other races of huachucana.

This snail is common throughout the Mustang range. The type was from the main canyon of the north slope of the largest mountain west of Dan Mathews' ranch, but the greatest number of living specimens were taken from the north side of the " tower " of the east peak of the range. A few albino shells were found. A deposit of fossil, or at least long dead shells, in this place, consists of rather small examples, between 19 and 22 mm. in diameter, 4 to 4-3/4 whorls.

Sonorella huachucana aguacalientensis Pilsbry & Ferriss Fig. 154.

Sonorella walkeri aguacalientensis Pilsbry & Ferriss, 1915. Proc. Acad. Nat. Sci. Phila., p. 396, pl. 9, figs. 5-6b, text-fig. 5.

The shell is similar to S. walkeri except that the ill-defined light bands bordering the chestnut band, and the middle region of the base, are only slightly paler than the light brown ground color (not nearly white, as in S. walkeri).

Height 13.8 mm., diameter 24 mm.; 4-2/3 whorls, or smaller, down to 19 mm. diameter.

Genitalia (Fig. 155) characterized by the length of the male ducts, much greater than in S. walkeri, but practically the same as huachucana. Length

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