32 DEVONIAN FISHES OF IOWA. 



Genus Acanthaspis 144 



Vertebral Centra 147 



Tuberculated Dermal Plates 149 



Ichthyodorulites 150 



Genus Onchus 150 



Genus Homacanthus 151 



Genus Ctenacanthus 152 



Subclass Dipneusti 157 



Order Arthrodira 158 



Family Macropetalichthyidae 167 



Family Mylostomatidae 177 



Genus Dinomylostoma 177 



Genus Mylostoma 179 



Family Coccosteidae : 184 



Genus Coccosteus 186 



Genus Brachydirus 187 



Genus Dinichthys 188 



Genus Protitanichthys 201 



Genus Titanichthys 203 



Genera of doubtful family position 205 



Order Ctenodipterini 207 



Family Ctenodontidae 210 



Genus Dipterus 210 



Genus Conchodus 227 



Genus Synthetodus 231 



Genus Scaumenacia 235 



Subclass Teleostomi 236 



Order Crossopterygii 237 



Family Holoptycbiidae 238 



Family Onychodontidae 240 



Suborder Actinistia 241 



Family Coelacanthidae 242 



Genus Coelacanthus 246 



Genus Palseophichthys 252 



Order Actinopterygii 255 



Suborder Chondrostei 255 



Family Pakeoniscidae 256 



Genus Rhadinichthys 257 



Special description of the auditory organ and other soft 



parts of R. deani, by Dr. G. H. Parker 272 



Genus Elonirhthys 273 



5 . Faunal lists 275 



Species of fossil fishes occurring in the Lower Devonian of North 



America 275 



Species of fossil fishes occurring in the Middle Devonian of North 



America 276 



Species of fossil fishes occurring in the Upper Devonian of North 



America 2S0 



6 . Acknowledgments 291 



"Die Natur ist das einzige Buch, das auf alien 

 Bliittern gewissen Inhalt bietet." — Goethe. 



