324 Difficulties of Darwinism. iJuly, 
the deserts which he inhabits, screens him from the observa- 
tion of his intended prey; it has pointed out that the tiger, 
lurking amidst the perpendicular stems of reeds, flags, and high 
grasses, is concealed by his vertical stripes. On the other 
hand, the rosettes and ocellated spots of the leopard, and 
other truly arboreal cats, are equally well adapted for hiding 
them amidst the foliage of trees. But surely the concealment 
of these latter species would have been still more complete 
had their ground-colour been some shade of green instead of 
buff, or stone-colour, as we actually find it. If Natural Selec- 
tion gave them their rosettes, why did it not act further in the 
same direction, and assimilate them to their haunts, not 
merely in design, but in colour? ‘There are, also, several 
species of beasts, frequenting grassy plains, which would 
have been much less conspicuous, and would have more 
readily escaped the observation of their enemies, had their 
colour approximated to that of the surfaces around them. 
The zebra is, in colouration and design, very similar to 
the tiger,—a resemblance which Swainson accounts for by 
declaring them both eminently sub-typical forms of their 
respective groups, as shown by their fierce and untameable 
dispositions. That the stripes of the tiger favour it in 
escaping the notice of its destined prey, and that they are 
therefore explicable on the principle of Natural Sele¢tion, is 
admitted. But is the zebra, when grazing, screened in the 
same manner from the observation of an approaching 
enemy? He frequents pastures similar in their general 
character to those sought by the concolourous horse and 
ass, and by the very imperfectly striped quagga. When 
feeding, further, he stands so much higher than a crouching 
tiger that he would be hidden only among very lofty reeds 
or grasses. Moreover, it may be remembered that a troop 
of zebras, when pasturing, generally have a sentinel placed 
in some suitable position, who warns his comrades if he ob- 
serves anything of a suspicious nature. He has, therefore, 
less need of a colouration calculated to mislead an enemy. 
The pattern of the giraffe somewhat resembles that of the 
leopard, but it is very questionable in how far it can promote 
his safety. He browses, indeed, upon the lower branches 
of trees in the outskirts of woods; but this is surely a very 
different position from that of the arboreal cats crouched 
aloft among the dense foliage. Even where his body is par- 
tially masked by bushes with which his spotted hide may 
harmonise, his long neck is very likely to attract attention. 
We can scarcely consider that either the zebra or the giraffe 
is a case of ‘‘mimetism.” The rough resemblance of the 
