20 SEA-SHORE LIFE 



after a few trials it is invariably rejected. The tentacles on the 

 other side of the animal will, however, conduct the paper to 

 the mouth even after those on the side first experimented upon 

 no longer accejot it, and it is evident that the experience of one side 

 of the animal has no effect iipon the other side. 



It seems reasonable to assume that if an animal can be trained 

 or can learn by exjDerience it has associative memory, and therefore 

 must be conscious, but it is certain that sponges, jellyfishes and 

 worms have no trace of associative memory. 



On the otlier liand Robert Yerkes has shown that the green 

 crab can learn to travel bj' the shortest path through a labyrinth to 

 its food. 



It is also believed that the squids and octopi, which are the 

 highest moUusks, have associative memory. 



However, practically all of the instincts of marine inverte- 

 brates are inherited, and the behavior of the animal is not altered 

 by personal experience or association with its fellows. They re-act 

 to external stimuli with almost machine-like regularity, and we 

 can generally predict what effect a ray of light, a current of elec- 

 tricity, the attraction of gravity or a change of temperature will 

 have upon the behavior of the animal. 



Essentially the same statements may be made concerning the 

 re-actions of our own heart, lungs and digestive organs, and there 

 is no more reason for the assumption that the lower marine animals 

 are conscious, than that these organs of ours are conscious. The 

 instincts of most marine animals are inborn and are inherited from 

 generation to generation, whereas in higher forms some of the 

 instincts are acc[uired by personal experience, and are not present 

 at Ijirtli or necessarily predestined to apj^ear during life. 



Interesting studies of this subject are given by C. Lloyd 

 JMorgau in "Animal Intelligence," London, 1896; and by Jacques 

 Loeb, in "Comparative Physiology of the Brain and Comparative 

 Psychology," 1902. 



It has been proved that each and every animal and plant be- 

 gins life as a single cell, and that the body of the individual is 

 built up as a result of the division and consequent multiplication 

 of this cell. Indeed, in one great group, the Protozoa the entire 

 animal consists of but a single cell, which performs all of the life- 



