PLATE V 



I and 2. Helicotoma peccatonica n. sp. Apical view and reconstructed 



transverse section of the coil. 



3 and 4. Ophihta alturensis n. sp. Apical view of the coil and cross sec- 

 tion of the same. 



5 and 6. Murchisonia putilla n. sp. Outline of the coil and of the umbili- 

 cal side of part of a coil with three or four volutions wanting. 



7 and 8. Rapbistoma leiosomellum n. sp. Apical view and an ideal cross 

 section of the coil. 



9 and 10. Rapbistoma lewistonense n. sp. Apical view and cross section 

 of a rubber cast of the exterior. 



II and 12. Murcbisonia argylensis n. sp. Natural cast of a smaller speci- 



men and an outline of the exterior of a shell obtained on a rubber cast. 



13 and 14. Rapbistoma ruidum n. sp. Apical surface of an interior cast 

 and ideal cross section of the same. 



15, 16 and 17. Rapbistoma minnesotense Owen. (15) Apical view of a 

 few of the first volutions; (16) a reconstructed cross section of an in- 

 terior cast ; and (17) a fragment of about the eighth volution. The up- 

 per fignre shows the upper surface with growth lines, the next is a 

 transverse section, and the last shows the lower surface. 



18. Rapbistoma owenin. sp. Apical view of the coil. 



19. Ho/opea o6esa Whitfield. A broken cast showing in part a transverse 

 section. 



20. StraparoUus intralobatus n. sp. Apical view and outline of the aper- 

 ture of the shell. 



31 and 22. Tryblidium repertum n. sp. Apical and side views. 



