346 



ANIMALS OF THE PAST 



Fig. 223. — Fossil scorpion. 



the great coal-forming period 

 of this era, we find traces of 

 spiders and several kinds 

 of insects; namely, locusts, 

 cockroaches, and dragon flies. 

 Fishes. — Fossils are found 

 indicating that fishes came 

 into existence early in the 

 paleozoic era, although not at 

 the beginning. These ancient 

 fishes were very different 

 from those Uving to-day. 

 Their bodies were, for the 

 most part, covered with bony 

 plates or smooth, hard, in- 

 flexible scales, quite imlike 

 the scales on living fishes. 



Fig. 225. — Paleozoic fish. 



