Exi'I.ANATIONS OK P[,ATKH. 323 



Figure 9 An inctnnplete exainple of medium nize in which the priniaiy ver 

 tical bands are broad and the secondary bands exceedingly narrow. 



Figui-e 10. A specimen of small size; showing the regularly alternating 

 ai-i-angement of the nodes. 

 Keokuk group. CrawfordnviUe, Indiana. 



pHYSOSPONdfA ALTKUNATA, Hall. 

 Page 195. 



Figure 11. A view of the original specimen; showing the narrow, subcylin- 

 drical form with large quadrules and subequal vertical strands. In 

 the latter there is some difference in size although not clearly shown 

 on the somewhat abraded sui-face here represented. 

 Keokuk group. Oraufordsville, Indiana. 



