344 MENTAL EVOLUTION IN ANIMALS. 



Again as regards Worms, Mr. Darwin has shown in his 

 work on the Earth-worm that this animal is of a " timid " 

 disposition, darting into its burrow ''like a rabbit" when 

 alarmed. Probably other kinds of worms, which are better 

 provided with organs of special sense and consequently have 

 more intelligence, may have more emotion. 



With reference to young children, Preyer is of the opinion 

 that the earliest emotion is one of surprise or astonishment 

 upon perceiving any change, or strikingly novel feature, in the 

 environment. In deference to his opinion, therefore, I have 

 placed Surprise upon the same level of emotional develop- 

 ment as Fear ; but of course in both cases this level is so 

 low that it is but the germs of such emotions that are here 

 supposed to be present. 



This earliest stage of emotional development (18) I have 

 made to correspond with " Emotions preservative of Self." 

 The next stage (19) I make to coincide with the origin of 

 "* Emotions preservative of Species ; " and of these the first 

 to appear are the Sexual. In the animal kingdom — or 

 rather let us say in the psychological scale — these emotions 

 are first unequivocally exhibited by the Mollusca,* which on 

 this account, as well as for the reasons given while treating 

 of the association of ideas, I have made to fill the corre- 

 sponding level on the other side of the diagram. 



The next level (20) is occupied by Parental Affection, Social 

 Feelings, Pugnacity, Emotions conducing to Sexual Selection, 

 Industry, and Curiosity. The level, therefore, corresponds 

 with the origin of the branch marked Social Emotions in the 

 central psychological tree, and with the earliest Eecognitior. 

 of Offspring on the side of the intellectual faculties. The 

 animals which first satisfy all these conditions are the Insects 

 and Spiders.f For here, even if we exclude the Hymenoptera, 

 we have evidence of parental affection in the care wliich 

 spiders, earwigs, and sundry other insects take of their eggs 

 and broods.f Again, numberless species of insects are highly 

 social in their habits ; others are highly pugnacious ; some 

 are conspicuously industrious ;t most flying insects (as we 

 have already seen in Chapter XVIII) display curiosity ; and, 

 according to Mr. Darwin's elaborate enquiries, it is also in 



* See Animal Intelligence, p. 26. 



+ For remarkable instances of this see ihid., p. 205 and p. 229. 



X Ibid., pp. 22rt-8. 



