BY N. DE MIKLOUHO-MACLAY. 1157 



peculiarity contradicts, or at least puts in doubt until further 

 observations, the general validity of the opinion expressed by 

 Wallace (I) and Darwin. (2.) 



This opinion was : that the directmi of the hair on the hack of 

 mammals is adapted to throw the rain off{Z). As an example of 

 the cor elation of the direction of the hair and the rain, the hair 

 on the arms of Simia sati/rus, observed by Wallace, has been 

 given (4). 



Observations of the attitude of the above mentioned marsupials 

 (principally of Dendrolagus Dorianus) during rain will be therefore 

 of great interest, and will give a striking evidence in favour, or 

 against the explanation of Wallace or Darwin. 



EXPLANATION OF PLATE 71. 



Fig. 1.— Upper part of the body of Dorcopsis luctuosa, D'Albertis $ in 

 profile, showing the peculiar direction of the hair on the neck. 



Fig. 2. — Dendrolariufi Dorianus, Ramsay, o "^ profile, to show the direc- 

 tion of the hair on the body. 



(1). A. B. Wallace. Contributions to the theory of natural selections. 

 A series of Essays, 2nd edition, 1871, p. 344. 



(2). Ch. Darwin. The descent of man, 2nd edition, 1882, p. 151. 



(3). Ch. Darwin. "The hairy covering of the body forms a natural 

 protection against the severities of climate and particularly against rain. 

 That this is the most important function is well shown by the manner in 

 which the hairs are disposed so as to carry off the water, by being 

 invariably directed downward from the most elevated part of the body." 



Wallace, Loc. cit., p. 344. "It can hardly be doubted that with 



most mammals the thickness of the hair on the back and its direction is 

 adapted <o throne off the rain." Darwin, Loc. cit., p. 151. 



(4). "A. E. IFftWace remarks that the conveyance of the hair towards 

 the elbows on the arms of the Orang may be explained as serving to throio 

 off the rain,"" Darwin, Loc. cit., p. 151. 



