448 CLASS REPTILIA. 



Laurenti was the first who separated the Hylje from the 

 frogs and toads. This genus is now universally adopted by 

 naturalists, and the viscous disks or cushions by which the 

 toes are terminated in the animals which compose it, consti- 

 tute their most obvious and leading characteristic. 



By means of these the hylse are enabled to attach them- 

 selves to smooth bodies, to climb, to leap from branch to 

 branch, and to traverse the moving leaves of trees, agitated 

 by the wind. More agile than the frogs, and endowed with 

 extraordinary suppleness, they make their way with dexterity 

 and nimbleness on the most flexible branches, where they are, 

 besides, steadily retained by the conformation of their toes. 

 Notwithstanding this, they are more tranquil than the frogs, 

 and are observed to await for entire days in the same place 

 in expectation of their prey. 



The hylse feed on all kinds of worms and small insects, 

 and during the fine weather they proceed on the leaves of trees 

 in the woods in search of aliment. Later in the season, they 

 retire to the bottom of waters, and, like the frogs, pass the 

 winter there in a state of lethargy. They also continue there 

 during a part of the spring, to couple, and to lay their eggs. 



In the day-time, and particularly when the heat of the 

 sun is greatest, they shelter themselves in shady places, where 

 the trees afford a thick foliage. They put themselves in 

 motion when twilight comes on, and sport in security. 



The cushions with which their toes are provided, are 

 simply fleshy, and of the form of a lentile. Examined with 

 the microscope, they appear porous sieves, from which an 

 unctuous humour very slowly exudes. They are generally 

 a little concave, and sometimes furnished with a very distinct 

 fold. 



The croaking of these animals has much analogy with that 

 of the frogs. It is only less sharp, and occasionally stronger, 

 especially in the males, which have under the throat a pouch. 



