592 THE DESCENT OF MAN. 



In the full-grown male Babirusa pig of Celebes (fig. 66), 

 the lower tusks are formidable weapons, like those of the 

 European boar in the prime of life, while the upper tusks 

 are so long and have their points so much curled inward, 

 sometimes even touching the forehead, that they are utterly 

 useless as weapons of attack. They more nearly resemble 

 horns than teeth, and are so manifestly useless as teeth that 

 the animal was formerly supposed to rest his head by hook- 

 ing them on to a branch! Their convex surfaces, however, 

 if the head were held a little laterally, would serve as an 



FifT. 67. Head of female -Ethiopian wart-hofr, from " Proc. Zool. Soc." 1869, 

 showing the same characters as the male, though on a reduced scale. 



N. B. When the engraving was first made I was under the impression that it 

 represented the male. 



excellent guard; and hence, perhaps, it is that in old 

 animals they ^' are generally broken off, as if by fighting."* 

 Here, then, we have the curious case of the upper tusks of 

 the Babirusa regularly assuming during the prime of life a 

 structure which apparently renders them fitted only for 

 defense ; while in the European boar the lower tusks 

 assume in a less degree and only during old age nearly the 

 same form, and then serve in like manner solely for 

 defense. 

 In the wart-hog ( Phacochoerus cBtliiopicus) (fig. 67) the 



*See Mr. Wallace's interesting account of this animal, "The 

 Mala^ Archipelago," 1969, vol. i, p. 435. 



