LATITUDE AND VERTEBRAE. 349 



inclosed waters, and in the waters of past geological epochs, the 

 process would be less completed, the numbers of vertebrae would 

 be larger, while the individual vertebra? remain smaller, less com- 

 plete, and less perfectly ossified. 



This, in a general way, is precisely what we do find in exam- 

 ining the skeletons of a large variety of fishes. 



The life of the tropics, so far as fishes are concerned, offers 

 many analogies to the life of cities, viewed from the standpoint 

 of human development. In the cities in general, the conditions 

 of individual existence for the man are most easy, but there also 

 competition of life is most severe. The struggle for existence is 

 not a struggle with the forces and conditions of Nature. It is 

 not a struggle with wild beasts, unbroken forests, or stubborn 

 soil, but a competition between man and man for the opportunity 

 of living. 



It is in the city where the influences which tend to moderniza- 

 tion and concentration of the characters of the species go on most 

 rapidly. It is adaptation or death to each individual in the city : 

 every quality not directly useful tends to become lost or atrophied. 



Conversely, it is in the " backwoods," the region farthest 

 from human conflicts, where primitive customs, antiquated pecul- 

 iarities, and useless traits are longest and most persistently re- 

 tained. The life of the " backwoods " may be not less active or 

 vigorous, but it will lack specialization. It is from the unused 

 possibilities of the " backwoods " that the progress of the future 

 comes. The high specialization of favored regions unfits its sub- 

 jects for life under changed conditions. The loss of muscular 

 power is often one of the results of skeletal specialization. 



The coral reef is the metropolis of the fish. The deep sea, the 

 arctic sea, and the isolated rivers these are the ichthyological 

 backwoods. 



An exception to the general rule in regard to the numbers of 

 vertebrae is found in the case of the eel. Eels inhabit nearly all 

 seas, and everywhere they have many vertebrae. The eels of the 

 tropics are at once more specialized and more degraded. They 

 are better eels than those of northern regions, but, as the eel is a 

 degraded type, they have gone further in the loss of structures in 

 which this degeneration consists. 



It is not well to push this analogy too far, but perhaps we can 

 find in the comparison of the tropics and the cities some sugges- 

 tion as to the development of the eel. 



In the city there is always a class which follows in no degree 

 the general line of development. Its members are specialized in 

 a wholly different way. By this means they take to themselves 

 a field which others have neglected, making up in low cunning 

 what they lack in humanity or intelligence. 



