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countenance of the elephant, together with his well-known 

 docility, lead to the presumption that this animal must possess 

 a brain of considerable magnitude. Although this is really 

 the case in a remarkable degree, yet the external skull is by 

 no means a measure of the organ within. I now place before 

 you a horizontal section of the cranium of this animal ; and it 

 exhibits two remarkable facts, first, the small space occupied 

 by the brain, and secondly, the beautiful and curious structure 

 of the bones of the head. To the latter we may first direct our 

 attention. The two tables of all these bones, except the oc- 

 cipital, are separated by rows of large cells, some from four 

 to five inches in size, others very small, irregular, and honey- 

 comb-like; these all communicate with each other, and through 

 the frontal sinuses with the cavity of the nose, also with the 

 tympanum or drum of each ear ; consequently, as in some 

 birds, they are filled with air, and thus, while the skull attains 

 a great size, in order to affbrd an extensive surface for the 

 attachment of muscles, and a mechanical support for the tusks 

 or the enormous incisor teeth, it is at the same time very 

 light and buoyant in. proportion to its bulk ; a property the 

 more valuable, as the animal is fond of the water, and fre- 

 quently takes to it, and swims and bathes in deep rivers. All 

 these cells are lined by a delicate mucous membrane of a light 

 rose colour, being slightly vascular, like that in the frontal 

 sinuses, of which cavities these cells may be considered as an 

 extension, rather than as analogous to the diploe in other ani- 

 mals. The septa between the cells are vertical, and pass from 

 the outer table to the inner; they are very hard and vitreous, 

 whereas the outer table is of a coarse and porous texture. 

 These septa strengthen the whole fabric, the outer table abut- 

 ting against them ; some rows are separated from others by 

 horizontal shelves. This structure also extends into some of 

 the bones of the face, and into those at the base of the cra- 

 nium, the pterygoid processes, and the condyles of the occipi- 

 tal ; but all the superior part of the last-named bone is devoid 

 of them, the two tables being close and thin, and the bone 



