84 PROCEEDINGS OF THE ACADEMY OF [Vol. LXXV 
In the Tucson Range, specimens were taken at Stations 58, 60 
and 61. As the original account of depressa was quite short, a 
fuller description is here given of a specimen from Station 58, 
pl, ‘fies i 
The shell is very thin, depressed, with a narrow umbilicus 
contained 9-10 times in the diameter. Between cinnamon-buff 
and light pinkish-cinnamon color, fading towards whitish on the 
base, with a chestnut-brown band above the periphery and more or 
less showing on the penult whorl, and having very indistinct, 
narrow pale borders. The surface is glossy, the last 2 whorls 
marked with fine smooth, growth lines under a lens; next earlier 
whorl having the lines irregular; after the nearly smooth first half 
whorl the embryonic whorls are minutely, closely but weakly 
rugose radially, and in the most perfect examples there are rather 
widely spaced protractive threads, as in S. binneyi. The spire is 
rather low; last whorl is very wide, viewed from above; it descends 
slowly and but little in front. The aperture is unusually large, 
peristome thin, distinctly but very narrowly expanded throughout, 
dilated at the columellar insertion, where it overhangs a small 
part of the umbilicus. Parietal callus arches forward somewhat, 
and bounded by a light raised line. 
Height- 11.5, diam. 19.3, diam. umbilicus 2 mm., 43 whorls. 
- 10, ives MIB ciniie 
= i IW ie aa I Ps a 
Genitalia (Plate VII, figs. 4, 5, 8) characterized by the rather slen- 
der penis with stout basal sheath, and containing a rather short, 
smooth, slender, blunt-ended papilla, contained 3 times, more or 
less, in the length of penis. Flagellum short. The vagina is 
shghtly shorter than the penis in specimens dissected (Stations 59 
and 61). Dimensions follow: 
Tiliageia, INGA cc cue: er een ye waene reer tee te One 118059 118061 
PGHIS US ete he en ee ee Rete ree eee ae 8 mm. 
Petiis tepals, 3: oes a alee Ae eee cee 2 ae he 
ra eS cea aaa hc erent rae eee ete rece eae E 8 123 
WEIR eR ise tie anaes oe reo ee 6.7 Shr ee 
Starr tin Sete Ch ee, ae, ae oe 61 58 
It differs from S. binneyi by the more fragile shell and slightly 
larger aperture. 
We at first thought that this might be S. arizonensis Dall, but 
that species, well figured by Bartsch, has not so large an aperture, 
a decidedly higher spire and less depressed body-whorl, and it is 
said to have ‘‘rather well-marked incremental lines and micro- 
scopic vermicular markings”’; the latter are certainly wanting in 
the present form, but may perhaps be due to the dead condition 
of the single specimen of arizonensis found. 
