178 



H. S. Lull — Evolution of the Elephant. 



necessary in wielding the huge trunk. The development of 

 this feature is beautifully shown in individual growth, for the 

 new-born elephant has a relatively long, low skull the walls of 

 which are slightly thickened so that the brain chamber fills 

 the skull completely as in most other mammals. During the 



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Fig. 6. Section of skull young ( x J), and old ( x £g) : from Flower's Osteology. 



course of growth, however, the skull walls thicken greatly 

 through the development of the air cells, while the brain cavity 

 increases comparatively little, just as one would predict from 

 the structure of the adult skull. 



