350 MENTAL EVOLUTION IN ANIMALS. 



have done so because this is the stage where, from inde- 

 pendent considerations already explained, I have assigned 

 the dawn of Keason (as distinguished from Inference), and 

 the lowest animal psychologically considered in which I 

 have found any evidence of this faculty is the crab.* 



Next we come to level 23 where I have placed the 

 Eeptiles and Cephalopoda: My reason for so doing is that 

 this is the level where I have represented psychological 

 development to have advanced sufficiently far to admit of 

 the recognition of persons, and this degree of advance has 

 undoubtedly been attained by the Eeptiles and the Cephalo- 

 poda.! It will be observed that I have bracketed this and 

 the two preceding levels together. My reason for doing so 

 is that the animals and the faculties named upon these levels 

 in some degree overlap. Thus the Batrachia are able, to 

 recognize persons,! and it is possible that Fish may be able 

 to reason, § while, on the other hand, the Eeptiles and Cepha- 

 lopoda are not in their general psychology so far above 

 the Batrachia and Fish as would be implied without the 

 bracket ; yet I should not be justified in placing them all 

 upon the same level, because I have no such definite evidence 

 that Batrachia and Fish are able to reason as I have in the 

 case of Crustacea, Cephalopoda, and Eeptiles. On the whole, 

 therefore, I think that the fairest mode of expressing these 

 various cross relations is the one which I have adopted. It 

 is not to be expected that our essentially artificial mode of 

 distinguishing between psychological faculties should so far 

 agree with nature, that when applied to the animal kingdom 

 our classification of faculties should always be found exactly 

 to fit with our classification of organisms, so that every 

 branch in our psychological tree should precisely correspond 

 with some branch in our zoological tree. Some amount of 

 overlapping must be expected, and in thus comparing the one 

 classification with the other my only surprise has been how, 

 in a general way, the two so closely coincide. 



On level 24 I have placed the Hymenoptera, together 

 with the distinction which I think most sharply marks off this 

 stage of mental evolution, i.e., the power of communicating 

 ideas — a power which ants and bees undoubtedly possess.|| 



* See Animal Intelligence, p. 233. J Ibid., p 255. 



t Ibid., pp. 259, 2G0-1, and 30. § Ibid., pp. 250-1. 



|| Ibid., pp. 49-57, and 156-60. 



