84 



THE CHAIN OF LIFE. 



&» 



Devonian these creatures ^ attained to gigantic sizes, exceeding 

 probably, any modern Crustaceans, and were tyrants of the 

 seas. Fterygotus anglicus {¥\g. 80) is supposed i-o have attained 

 the length of six feet. Yet these noble representatives of 

 the Crustaceans became extinct in the Carboniferous. On 

 the other hand, a few small king-crabs appear in the Upper 

 Silurian, and this type still continues, and seems to culminate 

 as to size in modern times j so diverse have been the fortunes 

 of these various groups. 



The higher, or decapod Crustaceans, now familiar to us in 

 the modern crabs and lobsters, are first found in a few small 



Fig. 80. — Fterygotus anglicus. Reduced. — After Page and Woodward. 



species in the Carboniferous, but they are preceded in the 

 Devonian by at least one species of the allied group of the 

 Stomapods (Figs. 81, 82). 



The Paheozoic age of geology is thus emphatically an age 

 of invertebrates of the sea. In this period they were dominant 

 in the waters, and until toward its close almost without rivals. 

 We shall find, however, that in the Upper Silurian, fishes made 

 their appearance, and in the Carboniferous amphibian reptiles, 

 and that, before the close of the Palaeozoic, vertebrate life in 



^ Fterygotus^ Eurypterrts, etc. 



