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 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 Eio 

 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 fir, is 

 scarcely discernible ; whereas, were it among some 



