282 



THE ANIMALS AND MAN 



species of all the great groups from simplest to higher are 

 living today. Most of these species are however modern 

 in their origin. The original or first species in all the great 



, 



FIG. 153. Skeleton of Hesperornis regalis, the Giant Toothed Bird of 

 the Kansas Cretaceous. (In the American Museum of Natural History; 

 after Sternberg.) 



groups are gone; and some whole families and orders of 

 species are extinct. For example in the class of reptiles 

 there existed in the Mesozoic era many enormous kinds 



