26o 



Bird-Lore 



hand very long, stiff feathers, the so-called primaries, are attached, while 

 other, somewhat shorter feathers, the secondaries, are attached to the hind 

 surface of the lower arm. These feathers overlap one another and thus form 



a large expansion, 

 which has the same 

 function as the large 

 skin expansion of 

 the bat and the 

 pterodactyl. 



Thus far we have 

 considered only the 

 true flyers. There 

 are, however, sev- 

 eral arboreal animals 

 that might be called 

 chute animals, since they are 

 'ided with membranes that can 

 pread and thus permit a gradual 

 FLYING FROG OF JAVA slanting descent through the air. 



Most of these animals are inhabitants of the Old World, some of the most 

 remarkable forms occurring in the East Indies. The membranes and 

 devices for spreading them present three modifications. In one form, that 

 of the flying tree-frogs of the East Indies, the toes of all the feet are greatly 

 lengthened and webbed up to their disc-like tips. These tips resemble the 

 toe-pads in our common tree-frogs. The figure shows the Javan flying 

 frog with its parachute spread in the act of gliding through the air. 



We find a second modification of the parachute in a small group of liz- 

 ards of the East Indian genus Draco, which comprises some twenty species. 

 These animals have five or six pairs of their ribs elongated and straightened 

 out at right angles to the body. The skin envelops the ribs and is spread 

 between them as a thin membrane. The Dracos live in the tree-tops, where 

 they hunt for insects, often gliding from twenty to sixty feet on a stretch 

 through the air in their descent from one branch to another. They rarely, 

 if ever, descend to the ground of their own accord. The parachute mem- 

 brane is, of course, always expanded and ready for use. Like the expanded 

 wings of butterflies, it is often banded and blotched with brilliant colors 



A third method of supporting the parachute is found in three distinct 

 and unrelated groups of mammals — the flying phalangers, the flying lemurs 

 and the flying squirrels. These animals are all nocturnal and all resemble 

 squirrels in size and coloration. They are all provided with a broad fold of 

 skin which connects the fore and hind limbs on either side, and which, like 

 the skin of the remainder of the body, is covered with fur on its upper and 

 under surfaces. The animals leap from the branches of trees, holding their 



