•670 



TBE DESCENT OF MAN 



ing them on a branch\ Their convex surfaces, however, if 

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

 cellent guard; and hence, perhaps, it is that in old animals 

 they "are generally broken off, as if by fighting." " Here, 

 then, we have a 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 



l:^^ 





S^.^ 



■-^rr 



P'' 









Fio. 66.— Skull of the Babirusa Pig (from Wallace's "Malay Archipelago"). 



defence; while in the European boar the lower tusks as- 

 sume in a less degree, and only during old age, nearly the 

 same form, and then serve in like manner so/ely for defence. 

 In the wart-hog {Phacochoerus cethiopicus, Fig. 67) the 

 tusks in the upper jaw of the male curve upward during the 

 prime of life, and from being pointed serve as formidable 

 weapons. The tusks in the lower jaw are sharper than 



* See Mr. Wallace's ir.teresUng account of this animal, "The Mala7 Archi- 

 pelago," 1869, vol. i. p. 435. 



