620 Contributions to Invertebrate Palaeontology. 



AXTHRACOPUPA Ohioensis Wliitf. Page 607. 



Fig. 15. View, greatly enlarged, of the back of the shell. 



Figs. 16 and 17. Similar views of the front and side showing the apertural 

 features and thickened lip. 



Spirorbis ANTiiRAcosiA Whitf. Page 608. 



Figs. 18 and 19. Upper and lateral views, greatly enlarged, of a specimen of 

 the prevailing form. 



Nautilus Ortoni Whitf. Page 601. 



Fig. 20. Lateral view of the specimen described showing the characters of the 

 shell. 



