64 
Sphaerium solidulum Prime ??? 
Plate VI, figures 3a-3d 
Shell approximately trigonal in outline, solid, inflated, 
umbones elevated anterior to centre of shell covered with fine 
ridges, growth lines coarse with finer lines between; ventral 
margin rounded, dorsal strongly arched. 
L. 8-5 H. 7-5 B. 6 
Locality. Lot 7, Eastview. 
Several specimens in the old collections at the Victoria 
Memorial Museum seem to be referable to this species. The 
writer was unable to find any specimens and it is included here 
with a query. It is a compact, stout little shell with a pro- 
nounced trigonal outline, and is quite different from either of 
the preceding forms. 
Pisidium abditum Haldeman 
Plate VI, figures 5a-5b 
Shell small, full, inequilateral, sub-oval; umbones placed a 
little behind the centre, inconspicuous; surface shiny, growth 
lines faint; dorsal and ventral margins rounded, anterior and 
posterior margins rounded; cardinal teeth small, lateral teeth 
conspicuous projecting above the edge of the valve, double in 
the right and single in the left valve, cavity of the beak small. 
L. 2*5 H. 2*0 B. 1*25 
Locality. McKay, Colton, and Mink lakes. 
Pisidium abditum is the most common of the small pelecy- 
pods in the marl. 
- Pisidium cf. compressum Prime 
Plate VI, figures 4a-4c 
The specimen figured resembles P. compressum, but varies 
from the typical form in not having the anterior margin pro- 
duced so far forward and in its less trigonal outline. 
L. 4*1 H. 3*9 B. 2*4 
Locality. Cob on lake. 
This form is rather uncommon. Other species of Pisidium 
will, perhaps, be found in these marl beds. 
