-* Fauna : Mammal^ 



of this pig are very brightly marked with long parallel stripes 

 of yellowish white on a blackish or umber ground. These 

 horizontal white lines on the upper surface of the body from 

 the nape of the neck to the tail are succeeded on the flanks by 

 short vertical stripes, with perhaps one or more horizontal 

 stripes along the sides of the belly. In fact, the young of 

 this Potamochcsrus seem to exhibit more clearly than the young 

 of any other known pig the white stripes of the primitive 

 ungulates. These, we know, may also be seen in the young 

 of the tapir. It is probable that the original markings in the 

 Horse family were white or light-coloured on a dark ground. 

 The fragment of hide that was found in a Patagonian cave 

 belonging to an extinct genus of horses {Hippidiutn) was 

 said to have b^en foxy red, marked with faint white spots. 

 In most of the existing species of horse the white stripes and 

 spots' have grown and extended until the original patches of 

 dark' hair between them (which also in most cases have darkened 

 from a bay-brown to umber or black) appear to be stripes, 

 instead of actually the last vestiges of the original dark colour 

 of the intervals between the white markings. When in this 

 way the lighter markings have so grown and extended that 

 ♦■hey have cleared away nearly all the dark colour, they have 

 arkened at the same time from white to mouse-colour or russet- 

 brown. These primitive ungulate spots and stripes of white 

 are retained by most of the chevrotains {Tragulida;), and by a 

 large number of ruminants (Pecora). 



The young of the wild boar of Europe and Asia, of some 

 of the Asiatic pigs of the genus Sus, and of all the pigs of 



' It is possible that the North European breed of dappled horses so frequently 

 seen in London streets — dappled in white and dark grey — may be descended from 

 a wild form which was largely spotted w-ith white on a dark grey ground. The 

 dapplings or faint light spots may be distinguished through the chestnut brown of 

 most domestic horses on the hindquarters. 



719 



