EXTINCT ANIMALS 



of the pelvis or hip-girdle are extraordinarily 

 like those of a bird. In fact it is now certain 

 that reptiles similar to the Iguanodon were the 

 stock from which birds have been derived, the 

 front limb having become probably first a 



Fig. 145. — Photograph of the skull of an Iguanodon as dug 

 out of the rock, showing the teeth of the lower jaw and the 

 smooth bony supports for the horny beak of both upper 

 and lower jaw. The specimen is three feet in length. 



swimming flipper or paddle, and then later an 

 organ for beating the air and raising the creature 

 out of the water for a brief flight. From such a 

 beginning came the feather-bearing wing of 

 modern birds. 



Fig. 146 shows the skeleton of a Dinosaur of 



202 



