MAMMALS 7 



gymnastic proclivities make it a very disturbing captive 

 in a European's house. 



A careful examination of the hand of a Gibbon shows 

 that in every way it is beautifully adapted for gripping 

 the branches of trees. It is very long in comparison 

 to its width, owing to the great development of the 

 metacarpals and phalanges. The thumb is very short 

 and is scarcely opposable, in fact not nearly to the 

 same extent as is the big toe. 1 Nearly all the creases or 

 lines, as a palmistry expert would call them, are for 

 the most part straight up and down, or transverse, 

 whereas these lines in the human palm are more or 

 less oblique. In the human hand the thumb can be 

 placed in opposition to each of the fingers, and the 

 movements of both thumbs and fingers are very com- 

 plex, but in the Gibbon the fingers are modified almost 

 entirely for gripping, and can do little but bend and 

 unbend. The fingers of the Gibbon on their palmar 

 aspect are very flat, and a long deep crease runs down 

 the middle of each. All the fine lines of the human 

 palm and fingers are much coarser in the ape, so that 

 a better grip is maintained with this roughened surface, 

 and on the fingers these coarse lines are arranged in a 

 chevron-like way converging on the middle crease, not 

 unlike the chevron lines on the driving wheels of 

 traction engines ; such lines are expressly designed to 

 prevent slipping, an object which is not attained so 

 well if the lines are directly transverse. Although an 

 examination of the Gibbon's hand shows that it is 

 wonderfully adapted for gripping, we also learn from 

 it how much man owes his position at the very summit 

 of the animal kingdom to the adaptation of his hand 



1 Cf. Fitzwilliams, Ann. Mag. Nat. Hist. (jSer.), XX. (1907), p. 155. 



