GECKOS. FAMILY IGUANID^. .;.;/ 



doubtful. From the peculiar structure of their toes ( 467), 

 they are capable of running along the smoothest surfaces, of 

 creeping up walls, and even of traversing ceilings, like a fly, 

 with the back downwards : they lurk in the chinks and fissures 

 of walls and trees, and in holes and crannies of buildings. From 

 the flatness and flexibility of their bodies, they are capable of 

 insinuating themselves into the smallest crevices ; and there they 

 lurk during the day, coming forth at night in quest of their 

 insect prey, and pursuing it with much activity, occasionally 

 uttering a kind of chuckling cry, from which their name is 

 derived. The Geckos are diffused through the warmer regions 

 of all quarters of the globe ; being most numerous in the tropi- 

 cal portions of Africa. 



494. The family IGUANID^E, or Iguanas, is a very extensive 

 one; numbering upwards of 150 species, many of which are 

 among the largest Saurians at present existing. Of the true 

 Iguanas, which are restricted to America, the general aspect 

 will be seen from the accompanying figure. They have a crested 



FIG. 324. IGUANA. 



ridge along the back ; and a curious dewlap, formed by a fold of 

 the skin, under the throat, which is capable of being distended 

 with air. The tail is long and flexible, and is laterally com- 

 pressed, as in the Crocodiles. The Iguanas are chiefly distin- 

 guished by the form and insertion of the teeth ; these are not 

 lodged in distinct sockets, but are fixed along the internal face 

 of the jaw-bone in a sort of furrow, and adhere by one side of 

 the bony substance of the root ; the surface of the teeth is irre- 

 gular, adapting them to grind down the vegetable substances on 



