374 PROCEEDINGS OF THE ACADEMY OF [June, 
Length 11.5, diam. 3.5 mm.; 123 whorls. 
Dragoon Mountains, Cochise County, Arizona, from Tweed Can- 
yon to the northern end of the range, on limestone, under stones, 
dead agaves, sotols, ete. Type locality Station No. 2, Tweed 
Canyon, No. 112,199, A. N.S. P. ) 
They live on the most exposed, hottest slopes, often in great 
profusion, but are not found on the mesa, where H. campestris 
occurs. 
This beautiful snail is very distinct from all of our species by its 
strong, rude, widely spaced ribs. One of the northwest Mexican 
Holospiras, H. minima, has the same type of sculpture, though less | 
coarse than in the typical H. danielsi, which is the most strongly 
costate species known. 
Like other Arizonian Holospiras, the internal lamellz are variable, 
_ two or three (parietal and axial, or parietal, axial and basal) being 
developed. Otherwise the chief variation is in the number of ribs, 
and also in size. 
Twenty specimens of the type lot, opened, taken at random, 
measure as follows: 
Length 12, diam. 3.6 mm.; whorls 13; lamelle 2. 
oo” MER Ra tg al pee ao hoe alton 
tl 0S eae ae ee olor It ge Fiske, est 
GE.) oa 3 a Re) ADE  e beee 
age 2) he Ae ts ema Sag Sees Ode soe 
poe 8) aes eo ees ae, Hees easy 
ia ich ce Bt ce ce 113; cc 3. 
cc We cc 3.4 ce iss 123; ce 3. 
rag tM: ce 3.3 ce ce 12; ce 3. 
(<3 ros (as BU cc iss 123; igs Ds 
cc Li “ 3.3 cc iss 12; ce aH 
BE OB a hie as ode 0 eet 
smd) SOM ta he es OE ASL Ee ey nena 
POE oo ee ae rw eee 
PRED Shae is? aon ie geen cs ees 
pepe) (Es Lae re Nes ath icy | aero eo ame 
Ses hOtec takes et i» Meas at 
eens 2 eacpages hs Cy aoe ye be 
cc 10, “ ok “c iss 113; a3 Oe 
es OSES eta ts MG ee Spier 
The smallest shell noticed in the type lot measures 8.2 x 3.2 mm., 
with 10 whorls. The trilamellate shells are slightly outnumbered 
by those with two lamella, forming 45 per cent. in the lot measured; 
but this may be accidental. Three lamelle predominate in the 
larger shells, two in the smaller. 
