202 The Naturalist in La Plata. 



ward of the flock, and when opposite to it suddenly 

 wheel and charge it at full speed, uttering loud 

 shouts, by which the birds are thrown into such terror 

 that they are incapable of flying, and are quickly 

 despatched. 



I have also seen gaucho boys catch the Silver-bill 

 (Lichenops perspicillata) by hurling a stick or stone 

 at the bird, then rushing at it, when it sits perfectly 

 still, disabled by fear, and allows itself to be taken. 

 I myself once succeeded in taking a small bird of 

 another species in the same way. 



Amongst mammals our common fox(Oanis azarse), 

 and one of the opossums (Didelphys azarse), are 

 strangely subject to the death-simulating swoon. 

 For it does indeed seem strange that animals so 

 powerful, fierce, and able to inflict such terrible 

 injury with their teeth should also possess this safe- 

 guard, apparently more suited to weak inactive 

 creatures that cannot resist or escape from an enemy 

 and to animals very low down in the scale of being. 

 When a fox is caught in a trap or run down by dogs 

 he fights savagely at first, but by-and-by relaxes 

 his efforts, drops on the ground, and apparently 

 yields up the ghost. The deception is so well 

 carried out, that dogs are constantly taken in by it, 

 and no one, not previously acquainted with this 

 clever trickery of nature, but would at once pro- 

 nounce the creature dead, and worthy of some praise 

 for having perished in so brave a spirit. Now, when 

 in this condition of feigning death, I am quite sure 

 that the animal does not altogether lose conscious- 

 ness. It is exceedingly difficult to discover any 

 evidence of life in the opossum ; but when one with- 



