86 



STORY OF THE REPTILES 



Heads 



The heads of the tortoise-forms are, in a rude waj, 

 quite birdUke, ending as thej do in a toothless horny 

 beak which often has on it a downward hook at the 

 tip. That of tuatera (or Hatteria) is more turtlelike 

 than most others which are not turtles, though certain 



Fig. 45. — Ehamphorhynchus. 



lizards tend to have horny beaks. In all these, how-, 

 ever, there are teeth. In a general way the heads of 

 snakes and lizards are much alike, though in some 

 snakes the neck is very much smaller than the head, 

 and the latter is then apt to be diamond-shaped. In 

 fact not till she got to the reptiles did JN^ature seem 

 much concerned about the neck, but at an early 

 date anionic the fossils some of these necks were ex- 

 tremely long and flexible. The heads of crocodilians 

 are long and flat, with a slight neck evident, which is 

 smaller than either head or body. But in lizards and 

 tortoises the neck is usually about as large as the head. 

 Perhaps in all modern reptiles the head extends 



