GREGORY: FISH SKULLS 447 



It has also been established by Spemann, Harrison and other modern embryologists 

 that during development "organizers," probably of a chemico-physical nature, preside 

 over certain regions of the developing embryo and have the power of directing and con- 

 trolling the development of parts and of linking them up one with another in such a way as 

 to produce viable individuals under a given set of environmental conditions. The problem 

 of inducing changes in the adult skull doubtless involves the problem of inducing the 

 "organizers" to relax their routine enough to permit one or more growth factors of skull 

 form to be modified at an early stage of development. If we can locate the "organizer" 

 or rather the organization that produces separate teeth on the premaxillse, we may some 

 day hope to modify it so that the teeth will coalesce into a beak. The operations of these 

 "organizers" show strong analogies with the operations of intelligent localized minds but 

 as these organizers in all probability do not have such minds, their behavior only indicates 

 that "mental" operations are caused by chemico-physical means. 



Thus the fourth paradox of purposive adaptations is that they are probably the unex- 

 pected by-products of blind chemico-physical organizers, forced by selective elimination to 

 vary from their "purposive" standards. 



In view of what I have seen of living fishes and their behavior, I would not be inclined 

 to deny that each individual fish has a mind, or that the summation of the responses of 

 individual fish minds has played an important part in adaptation and evolution. Just as 

 the responses of the mammalian and human nervous systems have played a great part in 

 the structural evolution of man, so have the gradually divergent responses of the fish nervous 

 system had an equally profound effect in determining the evolution of the mouth, jaws, 

 endocranium and all other parts in the adaptive radiation of fishes. In other words, the 

 hereditarily determined likes and dislikes of the fish itself^ together with its individual 

 psychic experience, have been an important factor in the evolution of its racial adaptations. 



Thus the fifth paradox of adaptation in the fish skull is that adaptation has been 

 brought about in part through the selective influence of individual fish minds, preferring 

 this kind of food and avoiding that, yet gradually changing their preferences, even through 

 slow shifts in the characters of whatever wholly unconscious genes may determine hereditary 

 types of reaction to different foods. 



However, even though there is a progressive integration of responses to more and more 

 remote contingencies, Ritter (1929) has well noted the shortsightedness or foolishness of 

 certain responses even in such relatively intelligent creatures as birds. In other words, a 

 generally beneficial reaction may, under changed conditions, become a dangerous or fatal 

 weakness. Thus each response of the individual fish is made without regard to remote 

 consequences and in the long run the guardian "minds" either of the fishes or of the or- 

 ganizers are not sufficiently wise to meet all the moves of their opponents and, in thousands 

 of cases, even the species itself loses the game. And seeing how full the organic world has 

 always been of waste, violence and stupidity, we can realize that natural mechanisms, in- 

 cluding fishes, are at best only animated, imperfectly conscious automata more or less 

 blindly struggling to capture food-energy and mates, according to their hereditary likes 

 and dislikes. The conception of the individual fish contributing through its own reactions 

 to the general evolution of the race has already been emphasized by MacFarlane (1923). 

 The coincidence and integration of helpful and appropriate responses by generations of 

 individual fish minds with the essentially anticipatory values of all physiological processes, 



