DlCTYOSPONGID^E. 



42] 



Figure 9. An incomplete example of medium size in which the primary ver- 

 tical bands are broad and the secondary bands exceedingly narrow. 



Figure 10. A specimen of small size; showing the regularly alternating 

 arrangement of the nodes. ' 

 Keokuk group. Crawfordsville, Indiana. 



PlIYSOSPONGlA ALTERNATA, Hall. 

 Page 387. 



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

 drical form with large cpiadrules and subequal vertical strands. In 

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

 on the somewhat abraded surface here represented. 

 Keokuk group. Orawfordsville, Indiana. 



