570 



FISHES. 



Sandstone — Chirolepis and Acrolejpis ; from Carboniferous 

 rocks — CosmojJtychius, Elonichthys, Nematoptycliius, Cydoyty- 

 cldus, 3ficroconodus, Gonatodus, Rhadinichthys, Myriolepis, 

 Urosthenes ; from the Permian — Bhabdolepis, Falceo7iiscns, 

 Amhlypterus and Pygoptcrus ; from the Lias — Centrolcjns, 

 Oxygnatkus, Cosmolcpis, and Thrissonotus. 



[See Traquair, " The Ganoid Fishes of the British Carboniferous Forma- 

 tions." Part I. Palcconiscidce.'] 



Seventh Family — Platysomid.'E. 



Body generally high, compressed, covered with rhoiiibic ganoid 

 scales arranged in dorso-ventral hands. Notochord persistent, 

 vnth the vertebi^al arches ossified. Heteroeercal ; fins with 

 fulcra; dorsal fin long, occupying the posterior hcdf of the 

 lack. BrancMostcgals oiumcrous. Teeth tubercular or obtuse. 



jj 



Fig. 147. — Platysoiuus gibbosus. 



Extinct. From Carboniferous and Permian formations — 

 Eurynotus, Benedenius, Mesolepis, Eurysomus, Wardichthys, 

 Chirodus (M'Coy), Platysomus. 



[See Traquair, "On the Structure and Affinities of the Platysomidte, in 

 "Trans. Roy. Soc.," Edinb., vol. xxix.] 



EIGHTH SUB-OEDER— AMIOIDEI. 



Vertebral column more or less completely ossified, hetero- 

 eercal. Body covered ivith cycloid, scales. Branchiostegcds 

 present. 



