PLATE 57. 
Figs. 1- 12. Leiorhynchus kelloggi. 
1 -3. Dorsal, ventral and profile views of a small individual. 
4. 5. Dorsal and front views of an attenuated form. 
6. Front view of a gibbous form, contrasting strongly with fig. 5. 
7-11. Dorsal, ventral, profile, front and cardinal views of a full grown and characteristic 
specimen of the species. 
12. Cardinal view of a cast, showing the cavities left by the removal of the dental lamellae, 
hinge-plate and septum. 
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861 
Figs. 18-17. Leiorhynchus sinuatus...... 362 
13. Ventral valve of a small individual. 
14-16. Dorsal ventral and front views of a small attenuated individual. 
17. Front view of a more gibbous form. 
Figs. 18-25. Leiorhynchus mesacostalis. 362 
18. Ventral valve of a small individual. 
19. Ventral view of a larger individual. 
20. Cardinal view of a large individual. 
21-23. Casts of dorsal valves, showing variations in form, and number of plications in the 
mesial fold. 
24. Ventral valve of a perfect and characteristic specimen. 
25. Cast of a ventral valve, showing the muscular impression and a narrow mesial sinus. 
Figs. 26-29. Leiorhynchus globuliformis. 364 
26-29. Views of dorsal valves of this species, showing the rotundity of the shell and the form 
of the muscular impressions. 
Figs. 30-39. Leptocoelia acutiplicata. 365 
30, 31. Dorsal and ventral views of a small individual, having a slightly concave dorsal valve. 
32, 33. Dorsal and ventral views of a specimen of medium size. 
34-37. Dorsal, ventral, profile and front views of a large and characteristic specimen of the 
species. 
38. Interior of a dorsal valve, showing a slender median septum, cardinal process and dental 
sockets. 
39. Enlargement of the interior of a ventral valve, showing the teeth and muscular impression. 
Figs. 40-45. Camarophoria eucharis. 368 
40-44. Dorsal, ventral, cardinal, front and profile views of a characteristic specimen of the 
species. 
45. Ventral view of a specimen, showing the triangular or spoon-shaped cavity of the ventral 
valve. 
