182 PRIMITIVE TYPES OF INTELLIGENCE 



conclusions. A starfish may possibly acquire habits of a 

 certain kind, but it is not proven that it is able to form 

 associations. 



We do not intend to deny the existence of intelligence in 

 the groups mentioned; we think it not improbable that 

 intelligence of a primitive sort may be discovered, at least 

 in the more highly developed members of these divisions; 

 but at the present time we can only grant the Scotch verdict 

 of "not proven." 



In the Arthropoda instinctive activity is frequently re- 

 presented as reaching its culmination, and some investigators 

 have gone so far as to assert that the behavior of these animals 

 is made up entirely of instincts and reflexes. This opinion 

 is in part based on a priori deductions from the organization 

 of the nervous system and it is held to chiefly by morpholo- 

 gists and physiologists whose observation of the behavior of 

 animals is limited and warped by preconceptions. 



Bethe, who has done a large amount of thorough and 

 valuable work on the anatomy and physiology of the nervous 

 system of arthropods, and who has very successfully employed 

 the results of these investigations in the analysis of normal 

 behavior, was led to the somewhat extreme position of 

 denying, not only associative memory, but consciousness 

 as well, in all the arthropods. The complex behavior of 

 these forms, according to him, can be analyzed in terms of 

 reflex action, and there is consequently no ground for assum- 

 ing any psychic elements whatsoever in these animals. 



At the close of his important memoir on the nervous 

 system of the crab Cardnus mcenas, there are described a 

 few experiments which convinced Bethe that this animal 

 is unable to profit by experience. Bethe placed a crab in an 

 aquarium containing a devil fish, Eledone, which took up 

 its station in a dark corner. The crab when placed in the 



