52 PROCEEDINGS OF THE ACADEMY OF [Feb.,. 
Thysanophora hornii,* H. F. Bifidaria pellucida hordeacella.. 
Agriolimax hemphilli ashmuni,” H. “«  quadridentata,” FH. 
Zonitoides milium meridionalis, H. “ pilsbryana, H. F. 
dg minuscula alachuana, H. s perversa.4 
Vitrea indentata umbilicata, H. ‘¢ ashmumi,4 HE: 
Helicodiscus eigenmanni arizonensis, H. . cochisensis,* H. 
Radiodiscus millecostatus,” H. it dalliana.“ 
Punctum californicum.” EY tuba. 
Vallonia perspectiva, H. F. Pisidium abditum huachucanum™, H. 
With the single exception of Agriolimaz, all of these are very small 
or minute snails, certainly capable of being carried long distances 
by cyclonic winds, and it is likely that their wide distribution may be 
attributed in part to such means, though it is not improbable that 
a considerable number of the forms may have existed before the 
isolation of the Arizona ranges. 
Twenty-two of the thirty species of groups 2 (a, b, c) have been 
found in the Huachuca range.'® These are indicated in the list above 
by the letter H. Four species, marked F in the list, occur in the far 
poorer fauna of the Florida Mountains. 
FAUNAL ZONES represented in the Chiricahuas are the Canadian, the 
Transition, and the Upper Sonoran. Zones dependent upon elevation 
are less distinctly marked in mollusks than in plants or vertebrates, 
local exposure and suitable conditions of moisture controlling the 
distribution of species to such an extent that the elevation zones are 
extremely irregular. It appears, however, that the Canadian zone 
forms are strictly confined to the high “parks”? and peaks. The 
characteristic Transition zone species are also for the most part high 
on the range, as are also five species which, from their distribution 
elsewhere, are considered to be Upper Sonoran. Seven of the eighteen 
Upper Sonoran species have been found only below 7,000 feet, while 
six have a general range. 
In the group of species peculiar to the Chiricahua range, and which 
must apparently be considered Upper Sonoran, many of the forms 
are very local in distribution and belong to the middle and lower zones 
of the range. Those having a wider distribution often have a great 
vertical range, as the following examples: 
14 Found only low, below 7,000 feet. 
4 As yet found only at about 8,000 feet or above, but none of them known 
from much further north than the Chiricahua range. 
18 Proc. A. N. S. Phila. for 1909, pp. 498-516. 
