532 NON-MARINE FOSSIL MOLLUSCA. 



PLATE 23. LARAMIE 

 CORBICULA OCCLDENTALIS Meek & Hay den. (Page 437.) 



FiQ. 1. Exterior view of the right valve of an example from Yampa River. North- 

 western Colorado. 



FIG. 2. Interior view of the same. 



FIG. 3. Dorsal view of the same ; the left valve restored in symmetry with the right 



FIG. 4. Left side view of an example from the same locality of less proportionate 

 height than usual. 



FIG. 5. Dorsal view of the same. 



FIG. 6. Copy of one of Mr. Meet's original figures. 

 (All natural size.) 



CORBICULA OBESA White. (Page 437.) 



FIG. 7. Exterior view, right side. 

 FIG. 8. Dorsal view of the same. 

 FIG. 9. Front view of the same. 

 FIG. 10. Dorsal view of another example. 

 FIG. 11. Interior view of a left valve. 

 (All natural size.) 



NEKITINA VOLVILINEATA W. (Page 458.) 



FIG. 12. Lateral view, enlarged. 

 FIG. 13. Opposite view of the same/ 



NERITTNA BRUNERI W. (Page 459.) 



FIG. 14. Lateral view, natural size ; showing color-markings. 

 FIG. 15. Opposite view of the same. 



NERITTNA (VELATELLA) BAPTISTA W. (Page 458.) 



FIG. 16. Dorsal view of the type specimen from Wyoming, showing the cdior- mark- 

 ings; enlarged. 



FIG. 17. Lateral view of the same. 



FIG. 18. Dorsal view of an example from Northeastern Colorado, showing the color- 

 markings ; enlarged. 



FIG. 19. Lateral view of the same. 



FIG. 20. Inferior view of the same. 



MELANOPSIS AMERICANA W. (Page 461.) 



FIG. 21. Lateral view, enlarged. 



FIG. 22. Opposite view of the same, showing aperture and broken outer lip. 

 FIG. 23. Similar view of the proximal portion of the same more enlarged, showing 

 callus of inner lip and canal. 



LIMN.EA (PLEUROLIMN^A) TENUICOSTATA M. & H. (Page 445.) 

 FIG. 24. Lateral view, natural size~and enlarged. After Meek. 

 CASSIOPELLA TURRICULA W. (Page 464.) 



FIG. 25. Lateral view of the type specimen ; the proximal volutions a little broadened 



by compression. 



FIG. 26. Similar view of another example. 

 FIG. 27. Similar view of a smaller example. 

 FIG. 28. Lateral view of another example showing the umbilicus, and approximately 



the outline of the aperture. 

 FIG. 29. Inferior view of a basal fragment of another example showing the umbilicus. 



