306 PLYING REPTILES, FISHES, AND MOLLUSCS. 



subsistence upon those which come within its reach, 

 it would stand a very good chance of starving. But, 

 aided by these marvellous developments of the feet, 

 it is able to spring at a passing insect, to catch it, and 

 to affix itself instantaneously to another branch or leaf. 



There are many species of Tree Frogs, spread 

 over a large portion of the earth, but the most re- 

 markable at present known is the Flying Frog of 

 Borneo, which was discovered by Mr. A. K. Wallace 

 in 1865. It was brought to him by a Chinese work- 

 man, who saw it skimming down from a high tree, in 

 a slanting direction, evidently upborne by the webs of 

 its enormously long toes. 



If the reader will refer to Cut 13, he will see the 

 Flying Frog shown in the act of passing through the 

 air, its toes being widely spread,, so as to stretch 

 the membrane which connects them. In proportion 

 to the size of the reptile, the extent of surface which 

 can be thus opposed to the air is very great. The 

 body of the Frog is about four inches in length, while 

 the web of each hind foot covers a space of four 

 square inches, and if the webs of all four feet be put 

 together, they will be seen to equal a space of twelve 

 square inches. It is evident enough, therefore, that 

 a creature which is only four inches in length, and 

 which is able to spread a flat membrane of twelve 

 square inches, would be upborne for some distance 

 through the air,, if it only projected itself with some 

 force. 



In this curious reptile, then, we have another or 

 the many ways in which a very simple variation of 

 structure is sufficient to make the creature a trespasser. 



