133 THE NATUEAL HISTOBY OF 



tration, to which we have added the letters of Dt 

 Burrough to its American describer. 



It is strongly characterised as distinct from the 

 other long-armed orangs or Gibbons. In form, size, 

 and proportion, it is most closely allied to the female 

 of the active Gibbon, H. agilis of F. Cuvier ; but is 

 very different in colours and markings, especially the 

 young individuals of the two species, which differ 

 totally in these respects. The male and female re- 

 semble each other in the present species ; but the 

 sexes of the active Gibbon are different in size and 

 colour. 



The specimen in the Edinburgh Collection agrees 

 nearly with that described by Dr Ha/lan . 



The colour of the young, according to Dr Harlan , 

 is blackish brown, sprinkled with gray on the hands 

 and feet ; the buttocks are grayish ; a tuft of the same 

 colour extends along the middle of the front of the 

 body ; the band of gray over the eyes of the adult, is 

 generally interrupted in the middle of the forehead by 

 a line of black hairs, which is absent in the young 

 one ; the band is broader in the latter, in proportion of 

 seven-tenths to four-tenths. In this individual, about 

 half the size of the adult, a remarkable difference was 

 observed in the relative proportions of the arm and 

 fore-arm. In the young animal, the fore-arm is shorter 

 than the arm a fact at variance with the proportions 

 of those parts, not only in the orangs, but in all the 

 race of adult Simice. In the adult, the arm and fore- 



