EXPLANATION OF PLATE XXII. 



Natica (Lunatia) hemicrypta Gabb (p. 118). 



Fig. 1. View of a specimen with the aperture oblique. 



2, 3. Two views ofoue having the aperture more upright. 



4, 5. Similar views of one having a slit in the inner lip and a smaller umbilical opening. 

 All figures somewhat less than twice natural size. 



N. (Lunatia) Tuomeyi Whiff, (p. 120). 



Fig. 6. Back view of a small individual. 



7, 8. Two views of a larger specimen, twice natural size. 



N. (Lunatia) heros Say (p. 119). 



FiG3. 9, 10. Two views, natural size, of the individual used in description. 



Crucibulum costatum Say (p. 122). 



Figs. 11, 12. Exterior and interior views of an imperfect specimen, the latter figure showing the inner 

 plate. 



13. Vertical view of a broad, flat specimen. 



14. Lateral view of a large crushed specimen. 



Trochita perarmata Conrad (p. 124). 



FlGS. 15, 16. Two views of a gutta-percha cast from a natural mold in the brown clays. 

 17. Lateral view of an exfoliated specimen of the usual size found. 

 18, 19. Other views of a similar form. 



188 



