DEVONIAN FISHES OF IOWA 



BY 

 CHARLES R. EASTMAN 



CONSPECTUS 



PAGE 



1. Aim and general outlook of palfeontological inquiry, and relations of 



palaeichthyology to biology 33 



2. Stratigraphy of the Devonian fish-bearing beds of Iowa 45 



Tabulation of the Devonian formations of Iowa 47 



Distribution of Fish-remains in the Devonian System of Iowa 48 



3. Evolutionary history of Fishes, and scheme of their systematic arrange- 



ment 51 



General Classiflcatory Scheme 65 



4. Systematic account of Devonian fishes, with special reference to those of 



Iowa and adjoining states 70 



Class Agnatha 70 



Order Heterostraci 72 



Orders Anaspida and Osteostraci 74 



Order Antiarchi 74 



Family Asterolepidae 75 



Genus Asterolepis 82 



Genus Bothriolepis 83 



Class Pisces 95 



Subclass Elasmobranchii 95 



Order Pleuropterygii 97 



Order Ichthyotomi 101 



Family Pleuracanthidae 103 



Genus Pleuracanthus 103 



Genus Diplodus 104 



Genus Phoebodus 105 



Family Cladodontidae 107 



Genus Cladodus 107 



Order Acanthodii 112 



Genus Machaeracanthus 113 



Genus Gyracanthus 114 



Subclass Holocephali 117 



Order Chimaeroidei 118 



Family Ptyctodontidae 120 



Genus Rhynchodus 123 



Genus Ptyctodus 133 



Accompanying detached parts, presumably referable to Ptycto- 



donts 138 



Dorsal Fin-spines 138 



Genus Heteracanthus 138 



Genus Acantholepis 140 



Genus Phlyctaenacanthus 143 



