194 Darwin, and after Darwin. 



A B 



FlG. 86. Comparative series of Brains. (After Le Conte.) The series reads from 

 above downwards, and represents diagrammatically the brain of a Fish, a Reptile, 

 a Bird, a Mammal, and a Man. In each case the letter A marks a side view, and 

 the letter B a top view. The small italics throughout signify the following homo- 

 logous parts: m, medulla; cb, cerebellum; d/, optic lobes; cr^ cerebrum and 

 thalamus ; 0/, olfactory lobes. The series shows a progressive consolidation and 

 enlargement of the brain in general, and of the cerebrum and cerebellum in 

 particular, which likewise exhibit continually advancing structure in respect of 

 convolution. In the case of Man, these two parts of the brain have grown to so 

 great a size that they conceal all the other parts from the superficial points of view 

 represented in the diagram. 



