34 MOSTLY MAMMALS 



The occurrence of bands on the legs and sometimes on 

 the shoulders of mules and dun-coloured horses, and like- 

 wise the presence of dark bars on the limbs of otherwise 

 uniformly coloured species of cats, like the Egyptian cat 

 and the bay cat, are further proofs of the same law. 

 Moreover, the fact that in the young of pigs — and, to a 

 certain extent, those of tapirs — the markings take the form 

 of longitudinal stripes, whereas in the more specialised 

 deer, whether young or old, they are in the shape of spots 

 arranged in more or less well-defined lines, is, so far as it 

 goes, a confirmation of the theory that spots are newer 

 than stripes. And the presence of transverse stripes in 

 the still more highly specialised antelopes tends to support 

 the derivation of this type of marking from spots, es- 

 pecially if it be remembered that the harnessed antelopes 

 are partly spotted. Still, it must be borne in mind that 

 these instances apply only to light markings, which, as 

 already stated, may have a totally different origin from 

 dark ones. 



There are, however, apparently insuperable difficulties as 

 regards longitudinal and transverse striping in mammals. 

 In the first place, instead of finding a number of the 

 polyprotodont, or more primitive marsupials, showing longi- 

 tudinal stripes, we have in this group only the three- 

 striped and single-striped opossums thus marked, and in 

 these the stripes are respectively reduced to the numbers 

 indicated by their names. This, however, is not all, for 

 the banded ant-eater takes its name from the narrow trans- 

 verse white stripes with which the back is marked ; while 

 the thylacine, which cannot in any sense be regarded as a 

 specialised type, is similarly marked with broader dark 

 stripes, neither of these animals having any trace of a 

 longitudinal stripe down the back. The water-opossum. 



