HO MEANS OF EXPRESSION Chap. IV. 



bird would ruffle its feathers whenever it attacked a 

 snake; and it is certain that the Herpestes, when it 

 eagerly rushes to attack a snake, erects the hair all over 

 its body, and especially that on its tail. 32 We have also 

 seen that some porcupines, when angered or alarmed at 

 the sight of a snake, rapidly vibrate their tails, thus pro- 

 ducing a peculiar sound by the striking together of the 

 hollow quills. So that here both the attackers and the 

 attacked endeavour to make themselves as dreadful as 

 possible to each other; and both possess for this purpose 

 specialised means, which, oddly enough, are nearly the 

 same in some of these cases. Finally we can see that if, 

 on the one hand, those individual snakes, which were 

 best able to frighten away their enemies, escaped best 

 from being devoured; and if, on the other hand, those 

 individuals of the attacking enemy survived in larger 

 numbers which were the best fitted for the dangerous 

 task of killing and devouring venomous snakes; — then 

 in the one case as in the other, beneficial variations, sup- 

 posing the characters in question to vary, would com- 

 monly have been preserved through the survival of the 

 fittest. 



The Drawing lack and pressure of the Ears to the 

 Head. — The ears through their movements are highly 

 expressive in many animals; but in some, such as man, 

 the higher apes, and many ruminants, they fail in this 

 respect. A slight difference in position serves to express 

 in the plainest manner a different state of mind, as we 

 may daily see in the dog; but we are here concerned 

 only with the ears being drawn closely backwards and 

 pressed to the head. A savage frame of mind is thus 

 shown, bat only in the case of those animals which fight 



32 Mr. des Vceux, in Proc. Zool. Soc. 1871, p. 3. 



