FOSSILS AND PEDIGREES 



361 



Jurassic. They have a fusiform body, strong jaws armed with 

 sharp teeth, and a forked tail (Fig. 1 3 1 c) . Many have a covering 

 of ganoid scales, but in others these are replaced by thin, cycloid 

 scales. From this family sprang the Amiidae, a tribe dating back 

 to the Jurassic, and differing from the Eugnathids in the large 

 dorsal fin, rounded tail, and thin, rounded, overlapping scales. 

 The sole living representative of this family, the Bow-fin 

 (Amia) , is to-day confined to the fresh waters of North America, 

 but this, or some nearly related species, has been found fossil in 

 European strata as late as the close of the Lower Miocene 



Fig. 131. PRIMITIVE NEOPTERYGIANS. 



A. Restoration of Lepidotus minor (Semionotidae), X ^ ; b. Dentition of 



Lepidotus mantelli . . . B', three teeth enlarged ; c. Restoration of Eiignathus 



orthostomus (Eugnathidae), X ij. (All after Woodward.) The scales have been 



omitted in figure C. 



epoch. The Pachycormidae have also been derived from the 

 Eugnathids, and were large-mouthed, predaceous fishes, not 

 unlike the modern Mackerels [Scombridae] in appearance. The 

 Aspidorhynchidae were long-bodied fishes, with the jaws prolonged 

 to form a beak as in the existing Sword-fishes. These are not 

 closely related to the Gar Pikes (Lepidosteus) , as was formerly 

 supposed, the latter having been derived from the main stem 

 at an earlier period, and probably descended direct from the 

 Semionotid stock. The Gar Pikes were abundant in Europe 

 during the Eocene and Miocene periods, but to-day are confined 

 to North America, where they made their appearance during 

 the Eocene. 



