504 ORGANS OF FLIGHT : FLYING FISH, PENGUIN, ETC. 



movement as one of flight, since it does not appear that they 

 have any power of propelling themselves in the air ; the 

 impulse being given at the moment of their quitting the 

 water, in the manner of a leap. From 50 to 100 yards, how- 

 ever, are sometimes traversed by the Fish at one leap ; and 

 the height to which it rises from 

 the surface of the water is occa- 

 sionally such as to carry it over the 

 deck of a ship. On the other hand, 

 there are several among the diving 

 Birds which use their wings as 

 instruments of progression beneath 

 the water in other words, as fins. 

 The most remarkably constructed 

 of all these is the Penguin (fig. 

 246), in which the wings are so 

 short as to be incapable of answer- 

 ing any other purpose ; but there 

 are several species in which they 

 Fig. 246.-PENGUIN. ma y fc e use d Qs, organs of flight 



in the air, without losing their fin-like power in the water. 

 There are several animals that can sustain themselves for a 

 short time in the air, by the aid of 

 an expanded surface formed by an 

 extension of the skin and serving 

 as a parachute. This is the case, 

 for instance, with the Galeopithecus, 

 or Flying Lemur (fig. 247), the 

 Flying Squirrel, and the Petaurus, 

 or Flying Phalanger (ZooL. 314), 

 which have the skin stretched out 

 on either side like a cloak, sup- 

 ported by the anterior and pos- 

 terior extremities and by the tail. 

 By this parachute-like surface they 

 are sustained in extensive leaps 

 from bough to bough; though it 

 does not enable them to support 



Fig. 247.-GAoPi.HKCU.. themselves in the air for any len g th 



6f time. In the Draco Volans (fig. 248), a little animal which 

 lives among the trees of tropical forests, the body is furnished 



