Fauna : Mammals 



the Cavalla River, this is strenuously denied by all the European 

 explorers and educated Liberians who have visited the Cavalla. 

 All persons, native and foreign, whom I have questioned on 

 the subject in Liberia declare that the only type of hippopotamus 

 known within the limits of that country is the pygmy form 

 ( Hippopotamus liberie nsis). 



The dwarf hippopotamus of West Africa is in some respects 

 slightly more specialised than its big relation. I am not aware 

 that it is specially related to the pygmy hippopotamus of Malta 

 and Sicily, now extinct. It is usually found with only one 

 pair of incisor teeth in the lower jaw (having, like the common 

 hippopotamus, two pairs of incisors 

 in the upper jaw). But this is not a 

 constant feature, as the number of 

 incisors in the lower jaw may some- 

 times be three. I give an illustration 

 of this from a skull in the British 

 Museum. The pygmy hippopotamus 

 is also thought to walk more on 

 the two middle toes of each foot 

 than on the whole four, the, side 

 toes being slightly raised from the ground. It has a larger 

 brain case and a shorter muzzle (proportionately) than the big 

 form. It has the same tendency to bristles on the broad upper 

 lip, though perhaps these are not quite so markedly developed 

 as in the big hippopotamus. There are a few bristly hairs 

 at the end of the tail. 



The coloration of the naked skin of the body differs from 

 that of the big hippopotamus in being more of a bluish or 

 greenish grey, without so much tendency to purple or to pink 

 or pinkish grey or pinkish brown on the lower parts and under 

 the great folds of skin. The colour of the living Liberian 



715 



277. LoVVKK JAW OF PIGMY HIPPO- 

 POTAMUS 

 Showing occasional three incisor teeth 



