980 



CLASS PISCES. 



the same horizon. The last and type genus Platysomus (figs. 919 

 and 920) is represented by a large number of species, ranging from 

 the Carboniferous of England and North America to the Middle 



Fig. 918. — Chirodzis granulosus ; from the Carboniferous of Scotland. 

 (After Traquair.) 



Reduced. 



Permian of England and the Continent. The contour of the body 

 is less rhomboidal than in Chirodus ; the dorsal and anal fins have 

 no anterior spines ; the pelvic fin is very small, and but seldom pre- 

 served ; while the pectoral is of medium size. 



Fig. 919.— Platysomus striatus; from the Middle Permian of England. Reduced. 

 (After Traquair.) 



Suborder 6. Lepidosteoidea. — In the Lepidosteoids the paired 

 fins are non-lobate; there is no infraclavicular bone; the rays of 



