FLYING FROG. 305 



side. Many naturalists have thought that the prin- 

 cipal object of this sac is to increase the buoyancy of 

 the animal while in the air. It does probably have 

 that effect, but I do not think that buoyancy is its 

 chief object, for the reason that the inflatable pouch 

 is found in many lizards which do not possess the 

 expansible sides, nor the power of skimming through 

 the air. 



The Flying Dragons are tolerably plentiful in 

 Borneo, Java, and the Philippine Islands, 



FLYING FROG. 



I presume that my readers are familiar with the 

 pretty Tree Frogs, which are now so plentiful in 

 ferneries. Their habits are curiously contrary to those 

 of the ordinary frogs, for they abandon both earth 

 and water for the trees, and lead an arboreal, and not 

 a terrestrial or aquatic life, as do their fellows. 



In order to enable them to ascend trees, they are 

 furnished with sucker-like appendages at the tips of 

 their toes, and with these they can cling firmly to any 

 smooth object, such as the trunk of a tree, the surface 

 of a leaf, or even a flat piece of glass. 



In the last- mentioned case, it is interesting to 

 examine with a magnifying lens the structure of the 

 suckers as they are pressed against the glass, and to 

 note how instantaneous is their action of exhausting 

 or admitting the air at will. This structure, indeed. 

 is absolutely necessary for the creature's existence. It 

 lives upon insects, and if it were to depend for its 



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