262 Bird- Lore 



food, running along the branches or gliding through the air with outstretched 

 parachute, from branch to branch or to the ground. 



The flying lemurs, of which there are only two species, occur in the 

 Philippines and neighboring islands. They are rather slender animals, about 

 the size of a small cat. Besides the expansion of skin between the fore and 

 hind limb, they have a smaller fold extending along the shoulder and front 

 surface of the arm as far as the wrist, and another larger fold between the 

 hind legs and embracing the tail. The toes of all the feet, too, are enveloped 

 in the skin-fold up to their claws. The flying lemurs are said to sleep hang- 

 ing to the branches with their heads down, like bats. When climbing about 

 in search of the leaves and insects on which they feed, the parachute mem- 

 brane is tucked up against the sides of the body. When the membrane is 

 expanded the animal resembles a kite, and in this condition it has been 

 known to traverse a distance of seventy yards at one glide, with a descent of 

 only one yard in five. The flying lemurs are peculiar in many points of their 

 structure, so that zoologists have found it difficult to give them a permanent 

 place in the classification. 



SOOTY TERN HOVERING 

 Photographed by F. M. C. 



This brief study of the wings and parachutes with which different animals 

 are provided leads us to an interesting conclusion. We see the same simple 

 function, flight, performed by a variety of structures, which have only the 

 character of an expansion in common. In most cases the expansion consists 

 of the skin of the animal, but in birds it is made up of overlapping feathers. 

 The skin expansion, again, may be supported in a variety of ways — by the 

 arms and legs in flying squirrels, by elongated fingers in the flying frogs, by 

 both elongated fingers and arms and legs in bats and pterodactyls, by elon- 

 gated ribs in the flying lizards, and, lastly, by a specially developed branching 

 framework in the wings of insects. Nature thus attains the same simple 

 end by employing a variety of methods. She never grows monotonous, for 

 her ingenuity and resources are alike infinite. 



