TREE-FROGS. 247 



discerning those who treat it kindly. If kept in 

 a garden, it proves a very useful inhabitant, by 

 its services in devouring noxious insects, and 

 particularly the small species of slug which is so 

 destructive to vegetation. The number of these 

 which a single Frog will devour is truly sur- 

 prising. 



Family II. Hylad^. 



(Tree-frogs.^ 



This is the most numerous in species of all the 

 Families of the Amphibia, and the one which 

 deviates most in its manners from the rest. The 

 Tree-frogs reside habitually among the foliage of 

 trees, among which they hop and leap almost 

 with the agility of the birds that tenant the 

 groves conjointly with them. They are able to 

 cling to the leaves on which they alight, with 

 exact precision, and to walk on them in all posi- 

 tions, and even on their under surfaces, without 

 falling off, just as a fly alights on the ceiling of a 

 room, and rests or crawls there. The smoothness 

 of the leaves, or other surfaces on which they 

 rest, offers no impediment to the secur;ity of their 

 position, for they do not derive their power from 

 the inequalities of the surface. " The monkey 

 grasps with its paws the perch on which it 

 rests ; the bird with its claws ; the snake twines 

 itself around the branch ; the iguana uses its 

 long toes and hooked nails ; the chameleon holds 

 the bough tight between its vice-like toes ; but 

 the foot of the Tree-frog acts differently from the 

 foot of these animals : it is not a grasping organ, 

 nor is it furnished with claws for clinging ; but it 



