L34 PALAEONTOLOGY OF ILLINOIS. 



Genus LEPTACANTHUS, Ag. 

 L. occidentalism N. and W. Sub-carboniferous. 



Genus CTENACANTHUS, Ag. 



Ct. gracittimus, N. and W. Sub-carboniferous. 

 Ct. costatus, N. and W. Sub-carboniferous. 

 Ct. angulatus, N. and W. Sub-carboniferous. 



Genus HOMACANTHUS, Ag. 



H. rectus, N. and W. Sub-carboniferous. 

 H. gibbosus, N. and W. Sub-carboniferous. 



Genus DREPANACANTHUS, N. and W. 



D. gemmatus, N. and W. Sub-carboniferous. 

 D. stellatus, N. and W. Sub-carboniferous. 

 D. anceps, N. and W. Coal Measures. 



DERMAL TUBERCLES. 



Genus PETRODUS, McCoy. 



P. occidentalis, N. and W. Coal Measures. 

 P. acutus, N. and W. Coal Measures. 



