36 The Ganoids 



Woodward unites the extinct genera called Cydurus, Not&us, 

 Amiopsis, Protamia, Hypamia, and Pappichthys with Amia. 

 Pappichthys (corsoni, etc.), from the Wyoming Eocene, is doubt- 

 less a valid genus, having but one row of teeth in each jaw, and 

 Amiopsis is also recognized by Hay. Woodward refers to 

 Amia the following extinct species: Amia valenciennesi, from 

 the Miocene of France; Amia macrocephala, from the Miocene 

 of Bohemia ; and Amia ignota, from the Eocene of Paris. Other 

 species of Amia are known from fragments. Several of these 

 are from the Eocene of Wyoming and Colorado. Some of 

 them have a much shorter dorsal fin than that of Amia calva 

 and may be genetically different. 



The genus Megalurus differs from Amia in the still shorter 

 dorsal fin, less than one-third the length of the back. The 

 body is elongate and much depressed. Megalurus lepidotus 



FIG. 26. Megalurus elegantissimus Wagner. Family Amiidce. (After Zittel.) 



and several other species are found in the lithographic stones 

 of Bavaria and elsewhere. 



The Oligopleuridae. --In the extinct family Oligopleuridcz 

 the scales are cycloid, the bones of the head scarcely enameled, 

 and the vertebrae well ossified. Fulcra are present, and the 

 mouth is large, with small teeth. The genera are Oligoplenrits, 

 lonoscopus, and Spathiurus, the species not very numerous 

 and chiefly of the Cretaceous. lonoscopus cyprinoides of the 

 lithographic shales of Bavaria is a characteristic species. 



From the three families last named, with the Pholidophoridcc, 

 there is an almost perfect transition from the Ganoid fishes to 

 teleosteans of the order of Isospondyli, the primitive order from 

 which all other bony fishes are perhaps descended. The family 

 of Leptolepidce, differing from Oligopleurida in the absence of 

 fulcra, is here placed with the Isospondyli, but it might about 

 as well be regarded as Ganoid. 



