LYMN-EIDZ OF NORTH AMERICA. 437 
Type Locatity: Sin-yale-a-min Lake, Mission Mountains, west- 
ern Montana. 
Anima, JAw, Rapura and Geniratia: Not examined. 
RANGE: Western Montana. A species of the Columbian River 
drainage (Columbian region) occupying an extension of the Boreal 
(Canadian) life zone. 
RECORDS. 
Montana: McDonald and St. Mary’s Lakes, Mission Mountains; Swan 
Lake and Sin-yale-a-min Lake, Mission Mountains (Elrod). 
GEOLOGICAL DisrripuTion: Unknown. 
Ecotocy: “The most noticeable snail, and the most difficult to 
secure, was Limnea emarginata, a small variety. The same species 
was found very abundantly in McDonald Lake, fifteen miles further 
to the north, and is also in Swan Lake across the range east. In 
Sinyaleamin Lake the shells are for the most part singly on stones in 
the bottom where the water is shallow, or along the bank. They are 
very light in color and very conspicuous. To secure them it is neces- 
sary to take a boat, row slowly where the water is shallow, and when 
one can be seen wait until the water becomes smooth and either pick 
it off by hand if not too deep, or by some other method. As there is 
much trouble to determine the depth of the water on such occasions, 
the task becomes quite difficult, and the result is often a wetting. Our 
best success was to take an insect net, and with this gently pull the 
shell off the rock by inserting the net under the snail, thus letting the 
animal fall into the net. Even this is slow work. The snails have 
the peculiar habit of letting all holds go when anything touches them, 
ialling to the bottom among the pebbles, where it is very difficult to 
seé them. An entire afternoon was spent fishing for these specimens, 
a couple of dozen being the number secured, and many getting away. 
It is readily seen from this that a small bottle may hold the entire 
catch of an afternoon” (Elrod). 
Collected in McDonald Lake along the rocks in the middle of the 
lake and at the outlet among grass and weeds in shallow water. 
Remarks: Montana may be known by its long spire, obese body 
whorl and rather open umbilicus. The inner lip is turned over more 
than in emarginata, and the body whorl is more obese and the columel- 
la smoother than in var. canadensis. It is a very thin shell. The sculp- 
ture is the most pronounced of any of the American species of Lym- 
nea. A peculiarity of montana is found in the obese character of the 
penultimate whorl. 
Montana seems to be entitled to specific rank, presenting a com- 
bination of characters not connected with emarginata by intermediate 
