242 THE AMERICAN JOURNAL OF SOCIOLOGY
As the organs of social transportation in becoming interna tional extend the limits of societies, so similarly the existence of marine currents tends to expand the boundaries of this vast domain. Certain species of the Indian Ocean are thus driven as far as Japan. From the Malay archipelago the fauna of the Polynesian seas presses its advance guards and its colonies as far as the Red Sea and the eastern coast of Africa. So throughout one zone, which measures not less than three-fourths the circum- ference of the globe and which embraces 60 of latitude, are found in general the same fish and the same mollusks. "The Cape of Good Hope forms a great barrier at which this gigantic empire terminates." J
The Atlantic is less homogeneous in its fauna than the Pacific. Between the fauna of the coasts of America and that of Africa there are some important differences. These are caused by the absence of islands and the great depth of the waters. Naturally, then, beyond 44 north latitude in the narrowest part some common species increase, such as salmon and codfish.
Maury appropriately adds:
In the water as in the air the necessity of finding nourishment and of assuring their reproduction forces some animals to long peregrinations. Most birds and fish are more or less migratory. Few species are absolutely con- fined to the same district; following the seasons or atmospheric variations, they change their residence. Among fish some travel singly and others migrate in pairs mackerel, sardines, codfish, and herrings; and so long as the geographical and climatic conditions are constant, their itineracy is con- stant also. Although confined to the polar sea, the several species of seals are not scattered indifferently upon the surface of the frozen water. Each has its particular district more or less extended.
Fish, of course, rise less in altitude than insects, birds, and mammals.
The same geographic, climatic, alimentary, and genesial con- ditions have exercised, and continue to exercise, a considerable influence upon the peregrinations and habitats of primitive human societies, and even upon modern societies. They continue to act in the present as in the past, although in a less simple and less general fashion, in proportion as societies adapt themselves
1 A. MAURY.
