304 PLYING BEPTILES, PISHES, AND MOLLUSCS. 



and the " false " ribs, which occupy the lower part of 

 the chest, and which have their ends free. It is by 

 means of the latter set of ribs that the expansion of 

 the sides is managed. 



The false ribs, instead of being, as they usually 

 are, much shorter than the others, are greatly length- 

 ened, or, to be more accurate, they are furnished with 

 very long and slender appendages. These additional 

 bones are so joined to the ribs that they can be spread 

 out laterally, or laid against the sides at the pleasure 

 of the animal. When they are spread, they very much 

 resemble the sticks of an opened fan, and as they are 

 connected with each other by a membrane which is 

 formed from the skin of the sides, they offer a very 

 wide surface to the air. 



The movements of the Flying Dragon are curiously 

 like those of the flying squirrels of the Old World, and 

 the flying marsupials of Australasia; and, indeed, if 

 the Flying Dragon and the opossum mouse were simul- 

 taneously to spring from one tree to another, their 

 sweeping flight would be almost identical, and it 

 would not be easy to distinguish between the two 

 animals. 



There is another point in the structure of the 

 Flying Dragon which has been thought to have some 

 effect in increasing its buoyancy when in the air. In 

 common with many arboreal lizards, it possesses a large 

 pouch under the throat, which it is capable of inflat- 

 ing to a very great extent. When the lizard is pre- 

 paring to launch itself into the air, it inflates this 

 sac simultaneously with spreading its wings, if we 

 may use this term to express its peculiarly constructed 



