ANIMALS OF THE PAST 



347 



Animals of the Mksgzok! Era 



In this era the reptiles increased in size, variety, and 

 number. Fishes, insects, and nioUusks Ijecame aljundant 

 and various, and more nearly a]:)proached the living forms 

 of these groups. Sea 

 urchins (Fig. 226) 

 much like our pres- 

 ent ones appeared 

 in abundance. The 

 lamp shells dimin- 

 ished in number of 

 species, but the 

 squids, cuttlefishes, 

 and other mollusks 

 appeared and peo- 

 pled the seas. Their 

 shells are found in 

 immense numbers 

 and are well preserved. The trilobites having disappeared, 

 crabs and lobsters came in their places. 



Reptiles. — It is among these animals that the greatest 

 changes are noted. There existed at this time three classes 

 of reptiles : land reptiles, sea reptiles, and flying reptiles. 

 They were very abundant and of extraordinary size and 

 variety. 



Flo. 220. — Sea urchin of iiiesozoie liine.^ 



Fjg. 227. — Sea reptile of luesozoic time«. 



