PALEONTOLOGY. 

 PLATE XII. 



Aporrhais (Goxtocheila) CASTOREXSIS Whitf 427 



Fig. 1. Enlarged view of a specimen, showing the extent of the posterior canal along the 

 spire. The expansion of the lip is seen a little more extreme on one other indi- 

 vidual. 



Anchura(Drepaxocheilus) xebrascexsis E. & S 429 



Fig. 2. View of a small individual, the labial spine strongly directed backward. 

 Fig. 3. A larger individual, varying somewhat in the form of the labial projection. 



Aporrhais xewberryi Meek 425 



Fig. 4. View of a specimen imperfect at the anterior end, but showing the labial spines for 

 some extent, though broken, and the posterior canal extending beyond the top 

 of the spire. 



Aporrhats meeki Whitf 426 



Fig. 5. View of the imperfect specimen, which, however, shows the characters of the 

 species. 



Axchura ? sublevis M. & H r 428 



Fig. 6. Enlarged view, showing the features of the species generally observed and the 

 stronger varices on the right side of the second and third volutions. 



Fusus shumardi H. & M 424 



Fig. 7. View of an imperfect individual, preserving the striae in part. 

 Fig. 8. Enlargement of the surface. 



Fusus cheyexxexsis Whitf 424 



Fig. 9. View of the specimen described, which is an internal cast. 



Fasciolaria (Crytorhytis) coxtorta Meek's sp 422 



Fig. 10. View of an imperfect individual, preserving the two lower volutions, and showing 

 their form and surface characters. 



Fasciolaria (Piestocheilus) culbertsoni M. & H 423 



Fig. 11. View of a specimen, preserving the two lower volutions, showing the surface char- 

 acters and form of the aperture. 



Fasciolaria (Crytorhytis) fusiformis H. & M.... 421 



Fig. 12. View of a fragment from the collection of Dr. Newberry, showing the lower volu- 

 tions with their characteristic markings. 



LUXATIA COXCLXXA H. & M 430 



Fig. 13. View of a specimen of the species, showing the form of shell and aperture. 



Vaxikora ambigua M.&H 430 



Fig. 14. View of a specimen, enlarged, showing the character of surface and form of shell. 



Margarita nebracensis M. & H 432 



Fig. 15. Enlarged view of a specimen, showing the general features of the species. 



Amauropsis paludix^eformis H. & M 431 



Fig. 16. View of the back of a specimen, natural size. 



Amisomyon patelliformis M. & H 435 



Fig. 17. Vertical view of an internal cast of this species, showing the muscular impression. 

 Fig. 1*. Profile view of the same, showing the elevation of the beak and its anterior posi- 

 tion. 



Axisomyox subovatus M. & H 434 



Fig. 19. View of a cast, showing the form of the shell and muscular imprint. 



Axisojiyox ala^eolus M. & H 433 



Fig. 20. Vertical view of a partially exfoliated specimen, showing the muscular imprint 

 in part. 



AXISOMYOX BOREALISMoit , 436 



Fig. 21. Vertical view of a specimen preserving a part of the shell. 

 Fig. 22. Profile view of an imperfect specimen, retaining the shell. 

 Fig. 23. View of a fragment, showing the radiating lines. 



Haminea subcylixdrica M. & H 437 



Fig. 24. Enlarged view of a specimen, showing the surface features and form of aperture. 



Akera glaxs-ORYZA Whitf 437 



Fig. 25. View of a specimen, greatly enlarged, showing its form and characters. 



Dextalium gracile H. & M - 438 



Fig. 26. View of an imperfect specimen, preserving the features of tho species. 



