MAN AND APES. 179 



a priori, less likely to be independently 

 acquired than a more or less developed chin, 

 such as man shares with the Siamang alone, 

 or a slightly aquiline nose, such as that found 

 in the Hoolock Gibbon and often in the 

 human species ? Can either character be 

 thought to have preserved either species in 

 the struggle for life, or have persistently 

 gained the hearts of successive generations of 

 female Gibbons ? .Certainly seductiveness of 

 this sort will never explain the arrangement 

 of the lobes of the liver, or the presence of an 

 oblique ridge on the grinding surfaces of the 

 back teeth. 



Again, can this oblique ridge of the 

 grinding teeth be supposed to have arisen 

 through life necessities ? and yet, if it is a 

 real sign of genetic affinity, how comes it to 

 be absent from the man-like Gibbons, and to 

 reappear for the first time in American apes, 

 and among others in the aberrant and more or 

 less baboon-like Howling Monkeys ? 



The same remark applies to the condition of 



n 2 



