67 
very large, oblique, oval, occupying nearly three-quarters of 
the whole shell. Peristome very thin, simple, with the termin- 
ation connected on the parietal wall by a thin callus; umbilicus 
absent. 
H. 11 W. 7-25 A.L* 8-5 A.H. 6 
Locality. Marl beds, .McKay lake. 
Succinea ovalis is a form whose very large aperture is sure 
to attract attention. The forms encountered here are smaller 
than usual. It is a rather common gastropod at present and is 
generally found close to water. 
Lymnaea stagnalis appressa Say 
Plate VII, Figures 12a-12b 
Shell elongated, thin; surface showing numerous rather 
fine growth lines; revolving lines numerous but irregular, very 
minute; whorls six to six and a half, rapidly increasing, es- 
pecially the last whorl, which, is much dilated and enlarged ; 
spire long, very acute; sutures distinct; aperture large, ovate; 
peristome thin, sharp, lower part rounded; umbilicus covered 
by a spreading callus. 
H. 19-5 W. 10-5 A.H. 10 A.W. 6 
Locality. Lot 7, Eastview. 
The above measurement is that of the best specimen 
found, but the average measurements of the species are over 
twice those given above. This Lymnaea is common at the present 
day and is plentiful in the marl beds in a fragmentary condition, 
but, owing to its thin shell and large size, it is seldom found 
complete. The large size of the last whorl compared to the 
others and the large aperture with its thin peristome, serve to 
distinguish it from other Lymnaeas. This form varies in height 
and width and has been given many varietal names. 
Lymnaea obrussa Say 
Plate VII, figures 1 la-1 lb 
Shell solid, elongate ovate in shape; surface dull, lines of 
growth coarse and covered by fine spiral lines, the body whorl 
occasionally malleated; whorls five or six regularly expanding, 
