340 PROCEEDINGS OF THE ACADEMY OF [May, 
sharply costulate; buff-whitish except where darkened by the 
presence of the soft parts, the last whorl shortly projecting; peris- 
tome narrowly expanded. Internal lamellz one to three, but axial - 
and basal most frequent. 75 individuals opened from the type locality. 
Southern and western portions of Sheridan Canyon, at Stations 
2,12 and 3. Types Nos. 112,268 A. N. 8. P., from Station 3, at the 
base of a cliff near the mountain top, facing the mouth of Sheridan 
Canyon, in company with Oreohelix ferrisst. 
Specimens from the type locality measure as follows: 
(1) An axial lamella only. 22 individuals = 293%. 
Length 16.9, diam. 4 mm. ; whorls 16 
16.6, + ifr 
“¢ 15; “ 4 “cc a3 154 
6c 14.2, ““ 4 cc ““ 15 
“cc 14, ce 27 “cr 6c 134 
a3 13:9; “ 4 (as a3 143 
Peas Came Ted) iq ae 
Galea meas SE l= wt cnamlds 
(73 12:2, vc 4 ce 6c 124 
‘c 12, a3 4 6c ce 123 
(2) Axial and basal lamelle. 48 shells = 64%. 
Length 18.5, diam. 4.25 mm. ; ; whorls 173 . 
16.5, 4.3 154 
ce 16.5 te (73 4 a3 73 16! 
GENO, € 450 4On8 , panei 
a3 16, cc 4 ce ia 16 
ce ae “ec 4 “ a3 154 
ce ina! ie (a3 4 c¢ “ce 154 
73 14.2, cc 4 a3 a3 15 
a3 13:5, ‘a3 4 ce cc 14 
“ce di, ce 4 ce cc 14 
cc 13, ce “4 cc ¢ 133 
cc 13, 6c 3.8 cc cc 14 
SGD Bee Se age eg ee 
NTR BBR) MONG ae aden aman 
73 12.1, ce 4 “ ce 13 
“cc it: ce 4 “ “cc 133 
(3) Three lamelle, superior, axial and basal. 5 shells = 62%. 
Length 18, diam. 4 mm. ; ; whorls 175 
17, 4.3 
17 
“c 16.5, “c 4 “c “ 163 
“ 16.4, tas 4 “cc 16 
“cc Se ce 4.1 ce “c 14 
