Animals Before Man 



walked on their hind legs, having three toes on 

 each hind foot and a variable number on the 

 front foot. This last group is sometimes called 

 Predentata, because the front of the lower 

 jaw is formed by an extra bone not found in 

 other animals, and preceding the tooth-bearing 

 bones of the jaw proper. The predentary bone 

 as well as the front of the upper jaw were 

 cased in horn to form a beak something like 

 that of a turtle. 



Dinosaurs began their existence in Triassic 

 times, but the few so far discovered are not a 

 tithe of those that remain to be found or that 

 never will be found. Of this we are certain, 

 for just as the first true lizard is represented by 

 footprints in the Carboniferous, so a goodly 

 portion of the reptilian horde left nothing more 

 than their tracks in the . red sandstone of the 

 Connecticut Valley, and these tracks, once 

 thought to be those of birds, are now known 

 to have been made by dinosaurs. These foot- 

 prints indicate not only a great many individ- 

 uals, but a great many species, large and small, 

 some that crawled about on all-fours, some that 



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