86 PROCEEDINGS OF THE ACADEMY OF [Feb. 
a.—Sculpture of sharp fine strize along the lines of growth, conspicuous 
on the base, where there are also spiral strize and some widely 
spaced larger spirals. 
b.—Sshell smaller, diameter about 11 mm., whorls 44 to 5; peripheral 
keel well expressed ee eer io ccbiasn «th. ceccan a eae ‘0. chiricahuana. 
b'.—Shell larger, diameter about 14 mm., whorls 54; peripheral keel 
strongly projecting, the whorl hollowed above and below 
Bs sds heteuspoc ed se ogee NE eR tacks TT ee eae ere O. c. percarinata 
Parca ene smoother ; spir ie Fans weak or wanting ; 
diameter usually 12 to 15mm., whorls 53 to 5$........ O. c. obsoleta. 
The type locality is on the slope with southern exposure below the 
cave in Cave Creek Canyon, Station 8 on map, p. 107. The dry 
ravine has steep sides of steeply dipping, more or less calcareous shale 
and earth formed by its decomposition. The dead shells are profusely 
scattered; living ones are under dead mescal (Agave), sotol (Dasyir- 
rion) and bear-grass, with Thysanophora horni, Succinea avara, Vitrea 
Fig. 10.—0. chiricahuana, Cave Creek, Fig. 11—0. c. percarinata P. and F., 
Station 8. Cross J Mountain 
indentata and Holospira. The colony here is about 250 yards long 
and perhaps 100 wide in the widest place. The shells are very uniform 
in size: 
INih erect veneer eae 6 6.8 6.5 6.5 6.8 6.8 mm. 
Dram 8 We aaiatmeege Me (NG a i i ih 10.5... ) 12s, 
The shells are white, with the earlier whorls flesh-tinted, a faint 
fleshy-corneous band at the outer third of the top of the last whorl, 
which has two grayish or fleshy corneous bands on the outer half of 
the base or a general fleshy corneous suffusion there. A scalariform 
mutation rarely occurs. 
From the cave we found large colonies at intervals westward nearly 
to the western rim of the valley, at Stations 5, 6 and 7 on map, p. 107. 
At Station 5, on a steep north slope along the creek, under rocks, 
about 3 miles west of the cave, the shells are similar but larger, 12 to 
13 mm. in diameter. 
