ACTINOl'TERYGII. 



S7 



Lyrne Regis (C. liassica) ; while a comparatively large species (C. australi*) 

 has been descril>ed from the Jurassic of New South Wales. 



During the Carboniferous and Permian periods a family of 

 deep-bodied fishes (Platysomidae) identical in all essential 

 points of structure with the Palseoniscida?, also flourished in 

 large numbers. The typical genus is Platysomus (fig. 64), 

 ranging from the Lower Carboniferous to the Upper Permian 

 in Europe, also known in the Carboniferous of North America. 

 Cheirodus, Mesolepis, and Eurynotus are other British Car- 

 boniferous genera. 



FIG. 04. 



Platijxomus gibboxus ; restoration by K. H. Traquair, about one-quarter nat. 

 size. U. Permian ; Germany and N. England. 



Though not becoming extinct until the period of the 

 Purbeck Beds, the PalaBoniscida? are comparatively rare in 

 strata above the Permian. Only eight or nine genera are 

 known with certainty, and individuals are very few above the 

 Triassic. Simultaneously with this decline, the short-lived 

 family of Catopteridae appears in the Triassic arid has a very 

 wide geographical distribution. The two closely related genera 

 of this family. Catopterus and Dictyopyge, are not very satis- 

 factorily known, the specimens being usually in a bad state 

 of preservation ; but the upper caudal lobe is clearly half- 

 atrophied, while the fins have much the aspect of those of tin- 



