Von Wrangel); the various coloration of many animals according to the composition of the forests they inhabit (the sable and the squirrel are well-known instances); the intermingling northern and southern faunas in the Amur region and the remarkable consequences of that intermixture in the struggle for existence; - all these render the study of the Siberian fauna most interesting.
The resultant intermingling of forms is very marked and characteristic of the Pacific Coast states.
All the fossil plants and animals of every kind are brought from this continent into a great museum; the latitude, longitude and relative elevation of each specimen are precisely recorded; a corps of investigators, having the most exact and thorough training in zoology and botany, and gifted with imagination, will soon begin to restore the geographic and physiographic outlines of the continent, its fresh, brackish and salt-water confines, its seas, rivers and lakes, its forests, uplands, plains, meadows and swamps, also to a certain extent the cosmic relations of this continent, the amount and duration of its sunshine, as well as something of the chemical constitution of its atmosphere and the waters of its rivers and seas; they will trace the progressive changes which took place in the outlines of the continent and its surrounding oceans, following the invasion§ of the land by the sea and the re-emergence of the land and retreatal of the seashore; they will outline the shoals and deeps of its border seas, and trace the barriers which prevented intermingling of the inhabitants of the various provinces of the continent and the surrounding seas.
This intermingling of types does not apply to south-eastern Mexico, where animal life is represented by many of the genera and species found in the forested lowlands of the great Amazon basin.
At the present time it represents an intermingling of marine and freshwater forms. To the former belongs the herring (Clupea), and to the latter, species of Cyprinus, Perca and Silurus, also a lobster.