RESEMBLANCES AMONG ANIMALS, 53 
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 oe distinguishable from the 
bark. 
Among birds, the eeaiaen: 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 till 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 
in 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 jir, is 
scarcely discernible; whereas, were it among some 
