382 COMPARATIVE ZOOLOGY OF CHORDATES 



maze perfectly, and then be placed in a similar maze but with 

 different lengths of alleys and distances between the turnings, 

 it will try to run the distances which it ran in the original 

 maze, and turn where the turnings were in it, and in so doing 

 it bumps into the walls of the new maze. Its learning was 

 therefore not intelligent. 



It is interesting to compare this case with that of a chim- 

 panzee confronted with a novel situation. In order to reach 

 food which was placed out of its reach, it hit suddenly on the 

 idea of piling packing-cases on one another and climbing up 

 on them. There is a good deal of evidence to show that in 

 order to " see " what to do in a set of circumstances, the ape 

 must really see the goal and the object which it may use as an 

 instrument, in the same field of view at the same time. There 

 is little doubt that the eyes have played an important part in 

 the evolution of the brain : in man the number of afferent 

 fibres running in from the retina is greater than that running 

 in from all the spinal nerves of one side put together. 



The possession of a cerebral cortex and neopallium does 

 not adapt the species to any particular set of environmental 

 circumstances, but instead, it makes all the members of the 

 species individually adaptable to a large variety of circumstances. 

 This is one of the chief differences between the higher and 

 lower vertebrates. All are well supplied with sense-organs, 

 but the lower vertebrates can only make a small number of kinds 

 of responses to the stimuli which they receive. The higher 

 vertebrates have much the same amount of information given 

 them by their sense-organs, but they use it to much better 

 advantage owing to the integrative and retentive properties of 

 the neopallium. The intelligent being does not waste time 

 on trial and error like Paramecium ; the probable results of 

 possible actions are weighed up in what must be called the 

 mind, with the help of experience stored up as memory, and 

 by means of thought, and the action when taken is intentional. 

 Lastly, it must be noticed that the possession of such a mind 

 and its physical basis the neopallium, confers an enormous 

 advantage on its possessor, and has survival value in evolution. 



