114 BULLETIN UNIVERSITY OF MONTANA 
something like twelve or fifteen miles. On the assumption that the 
shells would start from the water course, and possibly follow the ridge on 
the shady and damp side, they must have taken entirely different routes 
in ascending the two peaks. They were found abundantly on McDonald 
peak at the altitude 7,800 feet to about 8,500 feet. It is worthy of note 
that the shells seem to begin and end rather abruptly. When first 
found, on either mountain, they were found in considerable numbers. 
The high summits of McDonald are so steep, and the broken rocks so large 
in size, that there seems a limit to the range of the shell on McDonald. 
From our observations it appears that on the south side of Lake Mc- 
Donald thre is a break from the slopes immediately above the lake, with 
altitude about 3,400 feet, to 7,800 feet, in which no strigosa have beén 
found. They are probably there, but sparingly, since diligent search 
was made during the ascent. On the other bank, however, the northern 
slope, strigosa has been taken from the lake to altitude 7,500 feet, and 
continuously. Moreover, the shells taken at the high altitude on the 
north slope are many times the size of those taken on the opposite mount- 
‘ain. The locality in which the shells were taken on McDonald is on a 
ridge facing the west, bare of trees and other shelter, wind-swept, and 
storm-swept. On the north, on Teton mountain, the ridge faces the west, 
but is well wooded and protected, and apparently retains moisture much 
longer. To conchologists and others the wanderings of this shell will 
be of much interest, and the description has been given in some detail be- 
cause of that interest. 
A good series of Poiygyra tawnsendiana, var. ptycophora was secur- 
ed. The underbrush was so dense that it was necessarry to crawl on 
hands and knees most of the time among the shrubs and small trees. By 
digging in dead logs, overturning decayed stumps and branches and 
pulling apart dead leaves a good series was obtained, but at the sacrifice 
of clothing and flesh. 
Of these three species many were found eaten by squirrels. These 
were carefully preserved, and examination made of the method of proce- 
dure. The usual method was to break the shell at the apex of the spire, 
making a good sized opening. Through this the animal was drawn and 
no doubt afterwards devoured. A few openings were made at other 
places, and sometimes at very unfavorable places, due no doubt to lack 
of experience on the part of the enemy. Of the species P. strigosa, var. 
cooperi fifty were found thus broken into. Of P. solitaria four or five more 
than of cooperi, while P. townsendiana, var. ptycophora had but two thus 
eaten. As these latter much more resemble the surroundings than do 
the striped Pyramidulas this is not surprising, and is a good illustration 
of protection. 
On the talus north of the lake the bleached remains of a hitherto new 
shell were lying abundantly on the rocks. During the short stay at the 
lake in July, 1899, some forty specimens of this shell were secured, 
Pilsbury described it as a new species in Nautilus, Vol. XIV., P. 
40. The species is shown in Plate XXXII. It certainly is a species as 
distinct as many other described species, and certainly is unlike any other 
shell so far described in many respects. Whether or not intermediate 
