80 PROCEEDINGS OF THE ACADEMY OF  [Vol. LX XV 
The shell is rather narrowly umbilicate, dilute cinnamon tinted, 
fading to whitish around the umbilicus and on both sides of the 
chestnut-brown band. Surface somewhat glossy, with sculpture 
of weak growth lines only. Embryonic shell, after the initial 
smooth tip, minutely wrinkled radially, the wrinkles irregular, 
becoming interrupted and weaker after the first half whorl. Last 
whorl wide, rounded peripherally, moderately descending in front. 
Aperture rounded, nearly as high as wide, the peristome sharp, 
very slightly expanded, having a distinct thickening within. 
Height 9, diam. 15 mm.; 43 whorls. Type, Station 327. 
Diam. 14 to 17mm. Station 324. 
The penis is longer than the vagina, has a sheath nearly half its 
length, and contains a very short, thick, cylindric papilla with 
shortly conic end. The epiphallus is enlarged where it enters penis. 
A very short flagellum is present. Lengths of the organs follow. 
Misti INOS tere fond) oe et en ce ee eae 130628 130698 
PPOTRIG ot ens cae ceo reve Ahad Gott ce oe eee hae ee am 6.0 5.5 
Peni-papula ss: ee ee es aoa 2.5 2.3 
Brat piel: 9 oages. si Weald erent ee ces eee 6.0 ie 
SPLITS “sane eis sos Ge Be eae ne aunt. tae) ree 6.0 3.7 
Spermat neces Ang OUCE scr. 5.5 hu crecaete-stele et 16.0 be 
By the shape of the penis- papilla, the sculpture of the embryonic 
shell, etc., this race closely resembles S. sitiens; but the male 
organs are larger than in that, though the shell is much smaller. 
It differs from S. parva by the more rounded periphery and the 
very different genitalia. 
Sonorella sitiens comobabiensis P. & F. Plate VI, fig. 11. 
Originally described from the Comobabi Range; also reported 
from the Cababi Hills. The specimens we formerly referred to 
S. vespertina, from the Qui-i-tomoc Hills, appear on reexamination 
to be rather large S. s. comobabiensis. All of these were collected 
by the botanist J. C. Blumer. 
In 1918, it was taken at Station 125, a small hill south of the Ajo 
road, 12 miles west of Indian Oasis; and at Stations 1383, 1384, 135 
and 136, in the southern end of the Quijotoa Range. 
Specimens from Station 133 dissected show the peculiarly short, 
thick penis-papilla characteristic of S. sitiens alone; but both penis 
and papilla are longer than in typical sitiens, and the penial re- 
tractor muscle is inserted on the summit of the penis, not as in 
typical sitiens and S. s. montezwma, distinctly on the epiphallus. 
Length of penis 10, of papilla 2 mm. (Plate VI, fig. 11). 
