large Gecko verticillatus, which is extremely common in the East- 

 Indian Archipelago, utters a shrill cry, sounding like " tokee " or 

 "tock." 



The Varanidae, or Water Lizards, are the largest of Lizards, ^t?^ 8 ? 8 

 some exceeding a length of six feet. A few (Varanus griseus, 

 Case 11) are terrestrial, but the majority semi-aquatic, the former 

 having a rounded, the latter a compressed tail, with a sharp saw- 

 like upper edge, which assists them greatly in swimming, and at 

 the same time constitutes a formidable weapon with which these 

 powerful animals can inflict deep wounds on the incautious captor. 

 They range all over Africa, the Indian region, and Australia. Their 

 prey consists of other vertebrate animals — small mammals, birds, 

 frogs, fishes, and eggs. In India they are well known under the 

 misnomer " Iguanas " as dangerous neighbours to poultry-yards. 

 Among the species which grow to the largest size may be men- 

 tioned the gigantic Monitor ( Varanus giganteus, Case 16), from 

 N. Australia; the two-streaked Monitor (V. salvator, Cases 15-17), 

 common in the East-Indian Archipelago; the common Indian 

 Water-Lizard (V. bengalensis) ; and the African Monitor {V. 

 niloticus), ranging over the whole of Tropical Africa (Case 14). 



The Helodei-matida contain a single genus, the remarkable [Case 18.] 

 Heloderma horridum, an inhabitant of the western parts of Mexico. 

 As far as is known at present, it is the only Lizard whose bite is 

 poisonous. Its teeth are fang-like, provided with a deep groove 

 as in some Snakes, and the submaxillary gland is enormously 

 developed and secretes the poisonous fluid. It is about two feet 

 long. 



The Tejidce (bottom of Case 18) are the American represen- [Case 18.1 

 tatives of the Lizards proper, from which they somewhat differ in 

 their dentition. The Teguexins (Tupinambis teguexim and nigro- 

 punctatus) are the largest, attaining to a length of about four feet, 

 and found in most parts of the South-American continent. The 

 Dracaena guianensis is a rare Lizard, found in the Guianas and 

 Brazil, and was considered a kind of Crocodile by old authors, who 

 saw a distinct resemblance to those animals in its compressed, 

 keeled tail, as well as in the large tubercles which are arranged 

 pretty regularly on its back. 



Of the Amphisbaenidce, singular worm-like Reptiles, a few [Case 18.] 



