es the lion
and tiger, almost all the other large cats are arboreal in their
habits, and almost all have ocellated or spotted skins, which must
certainly tend to blend them with the background of foliage; while the
one exception, the puma, has an ashy-brown uniform fur, and has the
habit of clinging so closely to a limb of a tree while waiting for his
prey to pass beneath as to be hardly distinguishable from the bark.

Among birds, the ptarmigan, already mentioned, must be considered a
remarkable case of special adaptation. Another is a South American
goatsucker (Caprimulgus rupestris) which rests in the bright sunshine on
little bare rocky islets in the upper Rio Negro, where its unusually
light colours so closely resemble those of the rock and sand, that it
can scarcely be detected until trodden upon.

The Duke of Argyll, in his "Reign of Law," has pointed out the admirable
adaptation of the colours of the woodcock to its protection. The various
browns and yellows and pale ash-colour that occur on fallen leaves are
all reproduced in its plumage, so that when according to its habit it
rests upon the ground under trees, it is almost impossible to detect it.
In snipes the colours are modified so as to be equally in harmony with
the prevalent forms and colours of marshy vegetation. Mr. J. M. Lester,
in a paper read before the Rugby School Natural History Society
observes:--"The wood-dove, when perched amongst the branches of its
favourite _fir_, is scarcely discernible; whereas, were it among some
lighter foliage the blue and purple tints in its plumage would far
sooner betray it. The robin redbreast, too, although it might be thought
that the red on its breast made it much easier to be seen, is in reality
not at all endangered by it, since it generally contrives to get among
some russet or yellow fading leaves, where the red matches very well
with the autumn tints, and the brown of the rest of the body with the
bare branches."

Reptiles offer us many similar examples. The most arboreal lizards, the
iguanas, are as green as the leaves they feed upon, and the slender
whip-snakes are rendered almost invisible as they glide among the
foliage by a similar colouration. How difficult it is sometimes to catch
sight of the little green tree-frogs sitting on the leaves of a small
plant enclosed in a glass case in the Zoological Gardens; yet how much
better concealed they must be among the fresh green damp foliage of a
marshy fo