DEATH-FEIGNING IN TERRESTRIAL AMPHIPODS. 1 93 



feint ; at least the duration of the feint is increased when the body 

 of the animal is surrounded with sand or small stones. This 

 fact was determined by placing Talorchestias which had feigned 

 death upon a flat surface and counting the number of seconds 

 the feint continued and then comparing the series of observations 

 thus obtained with an equal number of observations made upon 

 specimens partly covered with sand or small stones. Fifty trials 

 were made and the average duration of the feint of the specimens 

 partly surrounded by sand or small stones was found to be much 

 longer than that of the specimens lying on a flat surface. As 

 TalorcJicstia is coming out of its feint a slight pressure or con- 

 tact causes it to resume feigning. 



There is little evidence that the death-feigning of Talorcliestia 

 is in any way connected with a conscious attempt at deception. 

 Such a performance is utterly beyond what the degree of psychic 

 development which the Amphipoda have probably attained 

 would lead us to expect. The instinctive action of Talorchestia 

 which seems most like an intelligent attempt to deceive an enemy 

 is that of crouching upon the approach of a threatening object. 

 Talorchestia when running away often crouches to the ground 

 and lies perfectly quiet if a large object draws suddenly near. 

 When things in its environment become quiet again the animal 

 moves on. Talorchestia does not feign death upon receiving 

 purely visual impressions ; it requires contact of some sort to 

 elicit this form of response. The same fact seems to be quite 

 general in the death-feigning of animals, especially below the 

 vertebrates, and it is a circumstance, I believe, of considerable 

 significance in relation to our views of the genesis of this instinct. 



The value of the death-feigning instinct in Talorcliestia is 

 obvious. When the animal is dug out of the sand its large size 

 would render it an easy prey to an active bird or mammal if it 

 attempted to seek safety in flight ; by lying quiet it is, as every 

 one knows who has dug these creatures out, very easily over- 

 looked on account of the resemblance of its color to that of the 

 sand around it. Its death-feigning and its protective coloration 

 both make for concealment and consequently are of service in 

 the life-history of the animal. 



The smaller sand-fleas Orchcstia palitstris and 0. agilis, live 



