Chap. XVII.] MEANS OF DEFENCE. 253 



surfaces would, however, if the head were held a little 

 laterally, serve as an excellent guard; and hence, per- 

 haps, 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 assum- 

 ing, during the prime of life, a structure which apparently 

 renders them fitted only for defence ; while in the Euro- 

 pean boar the lower and opposite tusks assume in a less 

 degree and only during old age nearly the same form, and 

 then serve in like manner solely for defence. 



Fig. 65.— Head of Ethiopian Wart-hoa:, from 'Proc. Zool. Soc' 1869. (I now 

 find that this drawing represents the head of a female, but it serves to show, 

 on a reduced scale, the characters of the male.) 



In the wart-hog [Phaeochoerus mthiopicus. Fig. 65) 

 the tusks in the upper jaw of the male curve upward dur- 

 ing the prime of life, and, from being pointed, serve as for- 

 midable weapons. The tusks in the lower jaw are sharper 

 than those in the upper, but from their shortness it seems 

 harHly possible that they can be used as weapons of at- 

 tack. They must, however, greatly strengthen those in the 



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

 Archipelago,' 1869, vol. i. p. 435. 



