IN BORNEAN FORESTS [chap. 



to such an extent as to form a parachute enabling it to float from 

 one tree to another. It is well known that the cobras {Naja) can 

 spread out the side skin of the fore part of the body, and could they 

 do this lower down they would be exactly like the flying lizards, in 

 which the skin-folds of the flanks are spread on free and lengthened 

 ribs. I may add that not only do the Malays and Dyaks believe in 

 the existence of flying snakes, but they have a name for them, and 

 call them " ular teddong-kumbang." l It should also be mentioned 

 that the Malays are most excellent observers of nature, and are well 

 acquainted with all forms of forest life. I can assert on my own 

 experience that I have never found their information in such matters 

 without foundation. 



The flying frog of Borneo (Rhacophorus reinwardtii) is described 

 and figured by Wallace in his well-known book on the Malay Archi- 

 pelago ; but it must be rare in that part of Borneo I visited, for I 

 never had the good fortune to meet with it. 



Besides bats and flying foxes (Pteropus), other flying mammals can 

 be seen any day in Sarawak. The commonest are the flying squirrels 

 (Pteromys), which I have already mentioned. But the strange 

 Galeopithecus volans is also abundant, and can easily be kept in 

 captivity. The skin expansions of this curious creature are more 

 developed than those of Pteromys, and not only do they, make an 

 efficacious parachute, but afford an ample cloak for the animal to 

 envelope itself during the daytime, when it sleeps. Flight in these 

 animals, in whom aerial locomotion was not a primitive condition to 

 which the entire organism has been co-ordinated, affords ample 

 ground for philosophical speculations. Considerations of safety, 

 and the necessity of being able to pass rapidly from one tree to 

 another may have supplied the needed stimulus, in a given species, 

 to endeavour to add to its powers of locomotion by adopting flight. 

 In other members of the same class, special powers in jumping or in 

 running may have a similar explanation. I have alwaj^s thought 

 that there must have been a formative epoch, in which every crea- 

 ture had the power of special adaptation to its own needs — nay, 

 even to its own wishes or caprice. In this epoch of " plasmation," 

 if I may so term it, when the so-called force of heredity — which tends 

 to reproduction according to the type of the progenitor — had but 

 little power, the world being still young, the organism must have 

 been far more susceptible of modification by external forces, and the 

 limbs more ready to adapt themselves to special usage. Considering 

 the very great number of animals that can fly, and how varied they 

 are, it is plausible to suppose that in the higher organisms the desire 

 to press upwards and skywards, whether to escape danger, seek food, 

 or to enjoy the heat and light, must have been general. This desire, 



1 In the Sarawak Gazette of January 4, 1886, flying snakes are mentioned 

 and it is added that there are two species of them. 



36 



