1860-61 < SCATTER-BRAINED' MAMMALIA 121 



suggested, scatter-brained. Then there was the 

 brain in which there was a curious apparatus of 

 cross fibres that brought every part of one hemi- 

 sphere in contact with the other. The next step 

 was where the cerebral hemispheres began to 

 increase in size, and there would not be room 

 in the skull to contain them if they were not 

 folded and packed as we should pack a nap- 

 kin in a box. This type of brain, which charac- 

 terised a certain class of Mammalia, was called 

 the wave-brain. Then there came a sudden and 

 marked step in the increase of the relative size 

 and complexity, number and depth of the con- 

 volutions of the brain, which was called chief- 

 brain, and marked a fourth well-defined group. 

 The loose brain was peculiar to two kinds of 

 quadrupeds that belonged almost exclusively to 

 Australia, and the duck mole and the kangaroo 

 might be taken as types of these orders. 



Owen then described the construction of various 

 mammals characterised by the different types of 

 brain, proceeding from the lowest to the most per- 

 fect in regular order. The gorilla he characterised 

 as the nearest approach to man. It was an animal 

 that had been known, from more or less perfect 

 specimens, for the last eight or ten years, and 

 from the enterprising traveller, M. Du Chaillu, to 

 whom we owed the most perfect of these speci- 

 mens, he had obtained the skeleton of a full- 

 grown gorilla, which was placed in the British 



