There are comparatively few animals in which the hair 

 does not slope in a very definite direction, from which it is 

 not easy to divert it, except for a moment, by reverse friction. 

 The most notable case is that of the mole, with its velvet-like 

 fur, so growing that it sets forward or backward on the 

 animal's body with equal ease. It seems to be the most 

 marked case of a burrowing animal with a coat very well 

 suited to its surroundings, and is only equalled by the aquatic 

 mammals such as otters, beavers, seals, whose hairy covering 

 is also very indifferent to the direction in which it sets. 

 Burrowing mammals generally are covered with hair 

 possessing much the same properties as that of the mole and 

 aquatic mammals, but these are less strongly marked, and in 

 forms of mammals with very long hair the direction of the 

 hair-slope is necessarily very easily determined one way or 

 the other by friction. 



The more simple and rudimentary the form of an 

 animal's body, the more simple and uninterrupted by varia- 

 tions is the direction of its hairy coat. An animal with 

 elongated form will exhibit the uniform set of hair which I 

 have mentioned as the type (from head to tail of the body, 

 and from proximal to distal ends of the limbs). Of this the 

 rodents and smaller cats afford excellent examples. From 

 the simple arrangements of the hair on rodents, smaller cats, 

 seals, and similar animals, through the ascending series of 

 more complicated forms of life up to man, an increasing 

 number of variations in the slope of hair as different groups of 

 animals are studied is found. They are so numerous, and each 

 genus or even species will show so many individual varia- 

 tions from the arrangement common in some region or other 

 to animals closely allied, that it will be impossible here to do 

 more than consider leading types of hair-slope in the 

 ascending series of animals, touching here and there upon 

 certain special regions of those types which are of interest. 

 It will be found, as we study many types of form and 

 structure in different groups, that not only is there this 

 general set of hair on body and limbs, which is itself very 

 variable, but that according to the complication of the form 

 and habits of the animals a considerable number of small 

 peculiarities in the arrangement of hair occur. Thus where 

 one stream meets another, or one stream divides from 

 another, or where some special seat of strong muscular 

 action is found, there are interesting small characters found 



