somewhat this arrangement, less marked, and in certain 

 oxen a whorl is often found on each side of the spine, in 

 others a single one which forms the starting-point of a 

 reversed slope of hair, and then passes forwards in a 

 feathering, and often ends in a crest. 



It remains to consider a few points as to the hair-slope 

 on portions of the limbs of ungulates and carnivores before 

 these great orders of animals are passed by. 



I have pointed out how the general trend of hair on the 

 limbs is from the proximal to the distal extremity of these, 

 and to a great extent this general trend is not departed from, 

 though the direction is seldom exactly in the long axis of 

 the limb. The most interesting and unexpected area of hair- 

 slope on the body of any animal is, I suppose, that on the 

 extensor surface of the forearm. It was this which led me 

 first to look into the question of the direction of the hair on 

 the bodies of animals and man. Wallace, Romanes, and 

 others have pointed out the singular reversed slope of hair 

 found on this surface of the forearm, and have endeavoured 

 to make out for it a vestigial character, as if it had been a 

 survival in man of a hair-slope very common in anthropoid 

 apes and American monkeys, which in them, according to 

 Wallace and Romanes, is adapted to their habit of sitting on 

 their haunches in their arboreal habitat, with their hands 

 raised and grasping boughs of trees. This adaptation is 

 supposed to be connected with the falling down of tropical 

 rain, the long hair of the arms acting as a thatch, and 

 running it off more effectually from the limb- Whether this 

 direction of hair is supposed to be produced for this very 

 singular purpose by natural selection, or by the constant 

 effect of rain so falling is not made very clear. I should be 

 disposed to maintain the latter view of it, if either. But I 

 sought to show in Nature in 1897 that, from its comparative 

 anatomy, this point of hair-slope cannot be considered in man 

 a vestige, but that in man and certain monkeys, apes, and 

 carnivores, and a few ungulates, which present this character, 

 it is produced by their habits of resting this surface of the 

 upper limb against the ground or other opposing objects 

 which it is not difficult to picture in the cases of different 

 forms of animals. I pointed out that the resultant of the 

 two forces — that of the weight of the animal acting 

 vertically downwards, and the weight of the fore-end of the 

 animal tending to slide forward — would be a force just 



