410 PROCEEDINGS OF THE ACADEMY OF [June,, 
mocensis, but the enlargement is largely concealed by the overhanging 
and dilated columellar lip. It is light pinkish cinnamon, fading to: 
white around the umbilicus, usually with a white streak on the last: 
whorl, left by a former resting stage, and with white bands above 
and below the rather wide chestnut-brown shoulder band. The 
apical sculpture is of the sitiens type, but some interrupted, descend- 
ing spiral threads are visible on the best examples; subsequent 
whorls are lightly marked with growth lines. The aperture is 
larger than in S. twmamocensis, but less ample than that of S. vesperus. 
The peristome expands distinctly, though narrowly. 
Alt. 10.1, diam. 18, longest axis of aperture 10.1 mm.;4# whorls. 
a3 10.8, a3 19, 73 ce ce “ce eS “c 43 ce 
“ec 9.7, “ 17.4, ec (as c ce 10.3 a3 42 ce 
Comobabi Mountains, at the base of a cliff on the north side of 
the highest part of the range, elevation about 4,000 feet. Type and 
paratypes No. 112,252, A. N.S. P., other paratypes in Ferriss col- 
lection. Also taken in the Cababi Hills, about 10 miles westward, 
in a slide of voleanic rock on the north side of the highest peak,. 
about 3,000 feet elevation. All were collected by Mr. J. C. Blumer, 
of Tucson, in the course of botanical exploration. 
About 120 specimens were collected, some of them showing the 
surface and color unimpaired, though all were dead shells. We are 
therefore unable to give any information on the soft parts. The 
shell is very much like S. sitiens of Las Gijas, further south, and east 
of the Baboquivari Range; but on account of the wide separation of 
the localities, it is likely to be subspecifically or even specifically 
distinct. 
The Comobabi Mountains form a short range, about 75 miles 
west of Tucson. The Cababi Hills, immediately west, and the 
Qui-i-tomoc Hills, a short distance south, are parts of the same 
group. It is evidently rich in shells, as Mr. Biumer found S. s. 
comobabiensis on the highest peaks (near the south end) of both 
Comobabi and Cababi, and a form which we cannot distinguish 
from S. vespertina on the north side of the largest peak of the Qui-i- 
tomoce Hills. Somewhere in the Cababi Mountains, the exact location 
not given, Mr. Frank Cole collected two forms, which we provision- 
ally refer to S. ashmuni as varieties; one of them isthe largest 
Sonorella known. 
Sonorella ashmuni capax n. subsp. Pl. X, figs. 7, 7a, 7b. 
The shell is umbilicate, the umbilicus very narrow within, but 
in the last half-whorl widening to about three times its former width, 
