INTELLIGENCE IN LOWER VERTEBRATES 227 



a cerebral cortex, which is lacking in the bony fishes, cannot 

 be said to surpass the latter in the development of intelli- 

 gence. The tailed amphibians are notoriously sluggish and 

 give every appearance of extreme stupidity. Nevertheless 

 they show a remarkably acute and delicate sensibility and a 

 power of very rapid action on occasions which is belied by 

 their general appearance and customary slow movements. 

 Our knowledge of their intelligence is slight. Few have 

 attempted to educate such apparently unpromising subjects 

 and neither Brehm, Buchner nor Romanes gives any re- 

 markable cases illustrative of their sagacity. Professor 

 Whitman, in his interesting account of the behavior of 

 Necturus, considers that this animal has a certain amount of 

 intelligence which is involved in its learning by experience 

 how to direct its movements, but he assumes nothing be- 

 yond this. Pieron has observed that if worms enclosed hi 

 a glass tube are introduced into an aquarium with specimens 

 of Triton, the amphibians make a large number of attempts 

 to seize the worms before showing any noticeable falling 

 off in the number of their fruitless efforts; fish under similar 

 circumstances learn to avoid the worms much more quickly. 

 In another experiment a quadrangular flask containing 

 several worms was placed on its side for a half hour a day 

 in an aquarium, containing six tritons. Sometimes the 

 animals found the entrance by chance and ate some of the 

 worms. With the exception of one individual which seemed 

 to learn the way fairly quickly there was no marked increase 

 in the facility with which the tritons entered the flask. The 

 experiment, while not thorough-going, indicates that asso- 

 ciations in these animals are usually formed but slowly. 



Among the Anura there have been several studies on the 

 intelligence of frogs and toads. These animals are capable 

 of forming simple associations, but their powers are very 



