96 
Plate VI 1 
Sphaerium simile Lamarck 
Figures la, lb. Exterior of right and left valves respectively. Marl beds, 
lot 7, Eastview, near Ottawa. (Page 63.) 
Figures lc, Id. Interior of right and left valves respectively. Locality same 
as above. (Page 63.) 
Sphaerium striatinum, Lamarck 
Figures 2a, 2b. Exterior of right and left valves respectively. X 2. Same 
locality as above. (Page 63.) 
Figures 2c, 2d. Interior of same. X 2. Same locality. (Page 63.) 
Sphaerium solidulum Prime 
Figures 3a, 3b. Exterior of right and left valves respectively. X 2. Same 
locality. (Page 64.) 
Figures 3c, 3d. Interior of same. X 2. Same locality. (Page 64.) 
Pisidium compressum Prime 
Figures 4a, 4c. Exterior and interior of right valve respectively. X 3 . 
Colton lake, Ont. (Page 64.) 
Figure 4b. Interior of left valve. X 3. Colton lake, Ont. (Page 64.) 
Pisidium abdilum Haldeman 
Figure 5a. Exterior of left valve. X 8. (Drawing.) McKay lake, Ont. 
(Page 64.) 
Figure 5b. Exterior of left valve, McKay lake, Ont. (Page 64.) 
Polygyra albolabris Say 
Figures 6a, 6b, 6c. Frontal, apical, and umbilical aspects respectively. Marl 
beds, McKay lake. (Page 65.) 
Pyramidula ( Patula ) alternata Say 
Figures 7a, 7b, 7c. Frontal, apical, and umbilical aspects respectively. 
Marl beds, McKay lake. (Page 65.) 
Succinea ovaUs Say 
Figures 8a, 8b. View of aperture and side opposite aperture. Marl beds 
McKay lake. (Page 66.) 
Helicodiscus lineatus Say 
Figures 9a, 9b, 9c. Frontal, apical, and umbilical aspects respectively. X3. 
Marl beds, McKay lake. (Page 66.) 
Polygyra ( Stenotrema ) monodon Rackett 
Figures 10a, 10b. Frontal and apical views respectively. Marl beds, 
McKay lake. (Page 65.) 
Figures 10c, lOd. Umbilical aspect, showing reflected peristome, long pari- 
etal tooth, and difference in size of umbilical openings. Marl beds, 
McKay lake. (Page 65.) 
1 In this and succeeding plates, unless otherwise stated, illustrations are 
of natural sifce. 
