Chap. Y. 
BATS. 
331 
antiquity. It is interesting to trace how the diversi- 
fication 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 tjrpe, such as is exhibited in the old world. 
America, for her share, has produced the most per- 
fectly 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 in- 
habiting the American continent are not Autochthones 
of America, the land of the Cebidse, but immigrants 
from the Old World continent, the land of the Anthro- 
poid 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 Heliconiae and other plants which grow 
