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LYMNZIDZ OF NORTH AMERICA. 
CLAY DEPOSITS. 
CanapA: Mr. Peel’s clay pits near Montreal (Bell); Pleistocene fossil, 
Montreal (Dawson). 
DRIFT. 
SoutH Daxota: Sioux Falls, Minnehaha Co. (Todd). 
Ecotocy: “Lymnea caperata I have found almost invariably in 
ditches and sloughs which are dry during part of the year, with nearly 
always a fine mud bottom; often in ditches entirely free from vege- 
tation, with obrussa, and again in sloughs containing much swamp 
grass, filled by spring overflow of streams.’ (Henderson, for Colorado 
specimens.) Among grass in marsh (Humboldt County, Nevada; 
Richardson). 
' Jn the Mississippi Valley this species seems to almost invariably 
occupy intermittent streams or small pools, ponds and ditches which 
dry up in the summer. In Illinois it is usually found in association 
with Aplera hypnorum and Spherium occidentale, either in small 
streams, pools or sloughs, or in spring pools in the woods which become 
completely dry in late spring and summer. The species hibernates 
to a greater degree than any of the other Lymneeas, a fact attested 
by the many rest varices observed on the shell of large individuals. 
In these dry ponds living specimens may frequently be found by dig- 
ging into the mud under leaves and other debris. The reports of Van 
Hyning for lowa, Walker for Michigan, Baker for New York and 
Sterki for Ohio show the same ecological relations of this species. 
Remarks: Although the statement has been made that caperata 
may prove a heterogeneous assemblage of different forms, it is never- 
theless true that it is one of the most distinct and uniform of American 
Lymnzas. The striking manner in which the epidermis stands erect 
in the impressed spiral lines is peculiar to this species and will always 
distinguish it when the specimens are fresh. Some small specimens 
resemble individuals of cubensis and humilis, and have been thus re- 
ported by various collectors. Caperata is one of the commonest of 
American Lymneas and is found over a very wide stretch of country. 
!t varies somewhat in the length of the spire and in the rotundity 
of the whorls, but this variation is not marked or uniform. (Plate 
XXVIII.) Specimens from Iowa, Illinois and Indiana are very large 
and robust. Many specimens are quite scalar and the color variation 
is wide. The shell is sometimes quite thin, though generally very solid. 
Individuals from Yukon Territory are smaller and paler than typical 
caperata, but offer no other tangible characters. They were compared 
with Say’s specimen by Dr. H. A. Pilsbry, who pronounced them iden- 
tical. Some specimens from California and Wyoming resemble buili- 
