49 



In tLj sea, in a '.vord, t.11 living beings arc far :.'.ore in- 

 intimately and directly dependent upon the environrient, and a^ t.^e 

 same time far nore at its mercy than they are on land. 



All the respects, so far discussed, in which the marine en- 

 viroranent differs from the terrestrial may be classified as 

 freedo-ri from danger: i.e., as negative rather than as positive 

 benefits. And it may be stated as a general rule that there is no 

 respect in which the sea is fundamentally unfavorable for lifi, 

 fatal thouzh imiuersion in sea water be to all the animals and plants 

 that through the ages have been attuned to a terrestrial existence. 

 With relief from unfavorable factors, coupled vith this fundamental 

 fitness of the sea water as an enviroranent, the evolutionary pro- 

 cesses are freed from many limitations and barriers in the sea, 

 allowing free expansion. Thus we find there an opportunity to steady 

 highly cor-plex colonial devolopments, and manifestations of the 

 division of labor, among lowly-organized groups. 



On the other hand, as a corollary to the freedom that marine 

 animals enjoy from sor:e of the most serious difficulties that beset 

 their relatives on land, even the most highly organized of them show 

 a low degree of mentality. Thus there is nothing among the_ 

 crustaceans comparable to the societies that some of their insect 

 relatives (ants', bees, t>:;rmitos, etc.) have developed. ITor have any 

 of the fishes of the sea developed anything of social organization 

 beyond such rudiments as the tendency of schools to hold together 

 in their wanderings. Thus in the sea the animal psychologist has 

 at his co:-uiand an^'ezcellent opportunity to examine v/hat may be 

 called the basic mental processes of a great variety of animals co:i:5- 

 paratively high in the evolutionary scale, unobscured by the co:>- 

 fusing psychic developments that have been stimulated on land by the 

 struggle against the unfavorable environment. 



The problems of large-scale behavior, as illustrated by the 

 phenomena of schooling, can certainly be studied to best advantage 

 in the sea - at least they can be most clearly seen there. And the 

 uniioriiity of the surroundings in which marine animals live malces 

 the sea a far more promising environment than is the land for 

 researches into the stimuli or receptive senses responsible for the 

 so-called "voluntary" migrations. 



It is still a mystery how fishes, and other marine anim.als are 

 able to direct their long journeys, often in darkness, and always 

 through a mediiom in which temperature, and chemical composition are 

 so nearly uniform over long distances that the most delicate tests 

 are needed to reveal any difference at points' many miles apart. The 

 problem here is akin to that of bird-migration. 



In short, the study of the basic life-processes is not 

 obscured in the sea by all sorts of protective adaptations: we there 

 come closer to the basic tasks of protoplasm, such as to incorporate 

 within itself materials from outside; to grow; to reproduce itatlf. 

 The sorts of biological problems that may be most profitably studied 

 in the two environments, marine and terrestrial, differ accordingly. 

 On land the most fertile results m.ay be hoped from, studying the 

 manifest adaptations by which animals and plants make their un- 



