282 THE STUDY OF ANIMAL LIFE CHAP, xm 



New Zealand "lizard," Hatteria or Sphenodon, which 

 may almost be called a living fossil. 



The Lizards (Lacertilia).--The lizards form a central 

 order of Reptiles, but the members are a motley crowd, 

 varied in detailed structure and habit. Usually active in 

 their movements, though fond, too, of lying passive in 

 the sunshine, they are often very beautiful in form and 

 colour, and sometimes change their tints in sympathetic 

 response to their surroundings or in expression of internal 

 moods. Most lay eggs, but in some, e.g. the common 

 British lizard (Lacerta vivipara), and the slow-worm, the 

 eggs are hatched within the mother. 



Among the remarkable forms arc the Geckos, which 

 with plaited adhesive feet can climb up smooth walls ; 

 the large Monitors (Varanus), which may attain a length 

 of 6 feet, and prey upon small mammals, birds, frogs, 

 fishes, and eggs ; the poisonous Mexican lizard (Helo- 

 derma horridum), with large venom-glands and somewhat 

 fang-like teeth ; the worm-like, limbless Amphisbcena ; 

 the likewise snake-like slow- worm (Anguis fragilis), which 

 well illustrates the tendency lizards have to break in the 

 spasms of capture ; the large Iguanas, which frequent 

 tropical American forests, and feed on leaves and fruit ; 

 the sluggish and spiny ' Horned Toad : (Phrynosoma) ; 

 the Agamas of the Old World comparable to the Iguanas 

 of the New ; the Flying Dragon (Draco volans), which, 

 with skin outstretched on extended ribs, swoops from 

 tree to tree ; the Australian frilled lizards (Chlamydo- 

 saurus), and the quaint thorny Moloch ; the single marine 

 lizard (Oreocephalus or Amblyrhynchus cristatus) from 

 the Galapagos ; and the divergent Chameleons, flushing 

 with changeful colour. 



The New Zealand Hatteria or Sphenodon is quite unique, 

 and seems to be the sole survivor of an extinct order- 

 Rhynchoccphalm. It was in it first of all that the pineal 

 body an upgrowth from the brain (third ventricle) of 

 backboned animals was seen to be like a degenerate 

 upward-looking eye. 



Snakes or Serpents (Ophidia).- -These much modified 

 reptiles mostly cleave to the earth, though there are 



