DEVONIAN FISHES OF IOWA 



197 



Fig. 28. 



Fig. 28. Dinichthys pustulosus Eastm. Middle Devonian; Iowa. Restoration of head- 

 shield, dorsal aspect, showing arrangement of cranial pKtes and course of sensory canals, 

 x J. Lettering as in figure 27 (see page 192) . 



Fig 



Fig. 29. Neoceratodus forsteri (KreffU. Dorsal aspect of cranial roof, drawn as if flat- 

 tened out to same extent as in Dinichthys. Cartilaginous portions dotted, and dermal 

 plates lettered to correspond with those in Arthrodires. The undivided anterior median 

 plate (P + R) is commonly termed the "mesethmoid." x 1-1. 



