Page:The naturalist on the River Amazons 1863 v2.djvu/351

 antiquity. It is interesting to trace how the diversification of forms (if the expression may be allowed), since the separation, has gone on in Tropical America. What wide divergence as to size, forms, habits, and mental dispositions, between the silver marmoset so small that it may be inclosed in the two hands, and the strong and savage black Howler, nearly two feet and a half in length of trunk! Yet there has been no direct advance in the organisation of the order towards a higher type, such as is exhibited in the old world. America, for her share, has produced the most perfectly arboreal monkey in the world; but beyond the perfection of the arboreal type she does not go. The retention of arboreal forms throughout long geological ages, may teach geologists that there must always have been extensive land areas covered by forests on the site of the tropical zone of America. It is curious to reflect, in conjunction with the fact of the advance of the American Quadrumana having halted at a low stage, that ethnologists have almost unanimously come to the conclusion that the race of men now inhabiting the American continent are not Autochthones of America, the land of the Cebidæ, but immigrants from the Old World continent, the land of the Anthropoid group of the order Quadrumana.

Bats.—The only other mammals that I shall mention are the bats, which exist in very considerable numbers and variety in the forest, as well as in the buildings of the villages. Many small and curious species living in the woods, conceal themselves by day under the broad leaf-blades of Heliconiæ and other plants which grow