MONKEYS— AFFINITIES AND DISTRIBUTION 181 



Miocene period several kinds, some of large size, lived 

 in France, Germany, and Greece, all more or less closely 

 allied to living forms of Asia and Africa. About the same 

 period monkeys of the South American type inhabited 

 the United States. In the remote Eocene period the 

 same temperate lands were inhabited by lemurs in the 

 East, and by curious animals believed to be intermediate 

 between lemurs and marmosets in the West. We know 

 from a variety of other evidence that throughout these 

 vast periods a mild and almost sub-tropical climate extended 

 over all Central Europe and parts of North America, while 

 one of a temperate character prevailed as far north as the 

 Arctic circle. The monkey tribe, in these remote periods, 

 enjoyed a far greater range over the earth, and perhaps 

 filled a more important place in Nature than it does 

 now. Its restriction to the comparatively narrow limits 

 of the tropics is no doubt mainly due to the great altera- 

 tion of climate which occurred at the close of the Tertiary 

 period, but it may have been aided by the continuous 

 development of varied forms of mammalian life better 

 fitted for the contrasted seasons and deciduous vegetation 

 of the north temperate regions. The more extensive area 

 formerly inhabited by the monkey tribe, would have 

 favoured their development into a number of divergent 

 forms in distant regions and adapted to distinct modes 

 of life. As these retreated southward and became con- 

 centrated in a more limited area, such as were able to 

 maintain themselves became mingled together as we now 

 find them, the ancient and lowly marmosets and lemurs 

 subsisting side by side with the more recent and more 

 highly developed howlers and anthropoid apes. 



Throughout the long ages of the Tertiary period 

 monkeys must have been very abundant and very varied, 

 yet it is but rarely that their fossil remains are found. 

 This, however, is not difficult to explain. The deposits in 

 which mammalian remains most abound are those formed 

 in lakes or in caverns. In the former the bodies of large 

 numbers of terrestrial animals were annually deposited, 

 owing to their having been caught by floods in the tribu- 

 tary streams, swallowed up in marginal bogs or quicksands, 



