DENTITION OF SOME DEVONIAN FISHES 41 
Fic. 4. Dipterus costatus sp. nov. Upper Devonian; Johnson county, 
Iowa. Left lower dental plate. 
Fies. 5, 5%. Dipterus uddent sp. nov. Cedar Valley limestone; New 
Buffalo, Iowa. Left lower dental plate, oval surface and profile. 
Fic. 6, 8. Difterus mordax sp.nov. Upper Devonian; Johnson county, 
Iowa. Somewhat worn examples of right lower dental plates. 
Fic. 7. Dipfterus calvint sp. nov. Cedar Valley limestone ; Fairport, 
Iowa. Right lower dental plate. 
| Figs. 4-8 reduced slightly less than natural size. ] 
C. R. Eastman. 
