504 



FOSSIL GANOID FISHES. 



include Ccdacanthus from the Coal, Macropoma from the Kimmeridge 

 Clay and the Chalk, Rldzodus, &e. The genera allied to Holoptychius 

 include Glyptolepis, Dendrodus, Glyptopomus, Gyroptichius, and other 



Fig. 139. Osteolepis restored. 

 . pectoral ; b. ventral ; c. anal; d, e. dorsal. 



Fins : a. pectoral 



Devonian and Carboniferous genera. The Pycnodonts were ganoids ; 

 they are represented by Pleurolepis and Homceolepis from the Lias, and 

 many genera of the Secondary rocks, such as Gyrodus, Microdon, 



Fig. 140. Holoptychius (fragment of jaw). 



Pycnodus, and Misodon, some of which range to the Tertiary. The 

 type represented by the living Lepidosteus is a large one. Lepidostens 

 itself is a Lower Tertiary genus. The Sauroid fishes are characteristic 

 of the Lias and Oolites, and comprise such genera as Semionotus, 

 Euynathus, Pholidophorus, Pachycormus, &c., Tetragonolepis from the 

 Lias. Lepidotus ranges from the Lias to the Chalk. Aspidorhynchus 

 characterises the Middle Secondary strata. The allies of Palceoniscus 

 range between the Old Red Sandstone and the Lias. CMerolepis, Cos- 

 moptychius, PalceoniseMS, Amblypterus, and Pygopterus are characteristic 

 Primary genera, while the Lias yields other forms like Centrolepis and 

 Cosmolepis. The allies of Platysomus are confined to the Carbonifer- 

 ous and Permian strata. The living American genus Amia is the 

 type of the last section of the Ganoids. Leptolepis characterises the 

 Lias and Oolites ; and Caturus, well known from Solenhofen, is found 

 in the Chalk. 



The Teleostean fishes are divided into six Orders the Acanthop- 

 terygii, Pharyngognathi, Anacanthini, Physostomi, Lophobranchii, 

 and Plectognathi. 



The Acanthopterygii are well represented in a fossil state. The 

 Perch is represented at Oeningen ; the Bass, Lalrax, the genus Ser- 



