136 MIND IN EVOLUTION CHAP. 



have been described in this chapter ? The same question 

 may be asked about other members of the animal kingdom, 

 of the same or perhaps of lower grade. Thus many 

 Crustacea prawns, for example 1 have regular " homes " 

 or lurking places. Even limpets 2 have been proved to have 

 fixed resting places to which they return, and the same is 

 true of snails. 3 A little reflection will show that the power 

 of " homing " does not amount to that general knowledge 

 of locality, involving many complex relations, which we shall 

 see reason to ascribe -to some at least among the higher 

 vertebrates. It does not necessarily imply anything beyond 

 a tendency to go back along the trail, which may well be 

 heredity. If this is so, the fixing of a home or a haunt 

 is in such cases an instance of the defining of an instinct 

 by experience an effect of primary retentiveness. The 

 homing tendency is fixed on a particular spot. In some 

 instances there is direct confirmatory evidence that 

 this is the true explanation. Snails leave a trail visible 

 to our eyes, and are known to follow it even when 

 it is irregular. 4 Even if there is no trail, if a fish, for 

 example, is guided by the objects near its haunt, we could 

 not safely assume a higher process than that of association 

 between perception and impulse. When the shark is 

 hungry the sight of the objects in the neighbourhood of 

 which it obtained prey attract it, and this influence might 

 spread to other objects on the way. There is nothing in a 

 monotonous out going or home coming that might not be 

 built up by habituation. 



Just as in "homing" or in lurking experience affixes an 

 instinctive tendency to one object rather than another, so 

 in chasing prey, fighting a rival, defending eggs, it makes 

 a given object a permanent source of excitability. At this 

 stage of intelligence, a quarrel, for example, does not cease 



1 Bateson, op. cit. p. 211. 2 Romanes, pp. 28, 29. 



3 Cambridge Natural History, Vol. III. p. 35. 



4 Ib. According to Bethe (Ameisen, p. 9), limpets, if moved a little 

 from their path, are unable to find their way. This observation, 

 however, is difficult to reconcile with the results obtained by Mr. Lloyd 

 Morgan, who shows (Animal Behaviour, p. 156) that from short 

 distances (up to six inches) the majority of limpets find their way 

 back. The successes rapidly diminish as the distance is increased to 

 two- feet. 



