REPTILES 223 



Common Iguana, which it resembles in the presence of a dorsal- 

 toothed ridge. The head, however, is smaller and rounder, and 

 there is a group of conical scales on the upper surface, while the 

 powerful tail is flattened from side to side and thus rendered 

 an efficient swimming organ, there being also an indication of 

 webbing between the digits. The food consists of sea-weeds. 

 Among the most bizarre species related to the Iguanas are the 

 Helmeted Basilisk {Basiliscus Americanus) of Central America 

 and Costa Rica, which perhaps suggested one of the fabulous 

 animals of mediaeval zoologists, the somewhat similar Capuchin 

 Lizard {Corythophanes cristatus) of Costa Rica, and the Cali- 

 fornian Horned "Toad" {Phrynosoma cornutum), xh& general 

 appearance of which certainly does suggest a spiny sort of toad, 

 possessed, however, of a tail. 



5. The Snake- Lizards, of which the name suggests the external 

 appearance, have their head-quarters in Central America and the 

 West Indies, but also occur north and south of this in the New 

 World, and are represented in Europe, North Africa, and India. 

 They not only possess horny scales but also underlying bony 

 scutes, which on the top of the head attain a relatively large size. 



The most familiar species is the Blind- Worm or Slow- Worm 

 {Anguis fragilis), common in Britain, and having a wide range 

 in Europe, occurring also in North Africa and in Asia. It is 



Fig 139 — The Scheltopusik [Ophisaurus apus), a blind-worm native to S Europe and S W Asia 



often mistaken for a snake, and erroneously regarded as exceed- 

 ingly poisonous. Its popular name dates back to the times 

 when the word " worm " was applied to serpents, and a survival 

 of this old usage appears to remain in some place-names, such 

 as " Worms " Heath, in Surrey. The Blind- Worm exhibits no 



