100 
Plate VIII 
Planor bis altissimus Baker 
Figures 18a, b. Apical aspect. X 3. Marl beds, McKay lake. (Page 7I.) 
Figures 18c, d. Umbilical aspect. X3. Marl beds, McKay lake. (Page 7I.) 
Figures 18e, f. Showing apertures of two individuals. X 3. Marl beds, 
McKay lake. (Page 7I.) 
Physa gyrina Say 
Figures 19a, b, c. Showing variation in apertures. X 2. Marl beds, 
McKay lake. (Page 72.) 
Figures 19d, e, f. View of side opposite apertures of three individuals. 
X 2. Marl beds, McKay lake. (Page 72.) 
Figure 19g. Apical aspect of a shell which was damaged and subsequently 
repaired by the living animal. X 2. McKay lake. (Page 72.) 
Figure 19h. Apical aspect of shell in which lines of growth are prominent. 
X 2. Marl beds, McKay lake. (Page 72.) 
Figure 19i. Apical aspect of another individual in which lines of growth 
are quite inconspicuous. X 2. Marl beds, McKay lake. (Page 72.) 
Amnicola lustrica Pilsbry 
Figures 20a, b. View showing two slender shells. X 3. Marl beds, Colton 
lake. (Page 73.) 
Figures 20c, d. View of side opposite aperture of two other individuals. 
X 3. Marl beds, Colton lake. (Page 73.) 
Valvata sincera Say 
Figures 21a, b. Apical and umbilical aspects respectively. X 3. Marl 
beds, Colton lake. (Page 73.) 
Amnicola limosa Say 
Figure 22a. View of side opposite aperture. X 3. Marl beds, McKay lake. 
(Page 72.) 
Amnicola porata Say 
Figures 22b, c. View of side opposite aperture, and of umbilicus respect- 
ively. X 3. Marl beds, McKay lake. (Page 73.) 
Figures 22d, e, f. Showing aperture and spire. X 3. Marl beds, Colton 
lake, near Renfrew. (Page 73.) 
Valvata tricarinata Say 
Figures 23a, b, c. Showing variation in carination of whorls. X 3. Marl 
beds, McKay lake. (Page 74.) 
Figure 23d. Apical aspect. X 3. Marl beds, McKay lake. (Page 74.) 
Figure 23e. Umbilical aspect showing base of whorl on which the carina is 
absent. X 3. Marl beds, McKay lake. (Page 74.) 
Figure 23f. Umbilical aspect showing base of whorl on which the carina 
is conspicuous. X 3. Marl beds, McKay lake. (Page 74.) 
