CHAP. XVII.] THE BRATN OF QTJADRUMANA. 



289 



representatives of the same genus or family, small forms 

 commonly have comparatively smooth brains ; while 

 larger animals present, in proportion to their size, more 

 and more richly convoluted Cerebral Hemispheres. 



In some of the Lemurs the Cerebral Hemispheres are 

 so small as not to cover more than one-half of the Cere- 

 bellum. There is, indeed, a kind of gap between the 

 lower and the lowest Simians that is between the old 



FIG. 107. 



PIG. 108. 



FIG. 103. 



FIG. 106. 



FIG. 103. Brain of an Aye-aye, one of the Lemurs. 



FIG. 104. Brain of the Marmoset (Midas). 



FIG. 105. Brain of the Squirrel-Monkey (Callithrix). 



FIG. 106. Brain of a Macaque. 



FIG. 107. Brain of a Gibbon. 



FIG. 108. Brain of a 5th month Human Foatus. (Owen.) 



and new world Apes and Monkeys, and the Lemurs. 

 " Every Lemur which has yet been examined," says Prof. 

 Huxley,* " has its cerebellum partially visible from 

 above, and its posterior lobe, with the contained posterior 

 cornu and hippocampus minor, more or less rudimen- 

 tary. Every Marmoset, American monkey, old world 

 monkey, Baboon, or Man-like ape, on the contrary, has 

 its cerebellum entirely hidden, posteriorly, by the cere- 

 * " Man's Place in Nature," p. 96. 



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