EINAR LÖNNBERG, THE GENUS POTAMOCHCERUS. 3 



or påle area, or a big spöt on eitlier side of the nozzle. The 

 general colour varies a great deal but it is of ten dark. 



The western P. porcus-grou-p is covered with shorter 

 hair, especially in adult animals, but the fur appears to be 

 denser so that the skin as a rule is concealed. The dorsal 

 crest is well conspicuous in consequence of its white colour, 

 but the hair by which it is formed extends very little, some- 

 times not at all, above the general hairy covering. This 

 white dorsal stripe generally begins behind the level of the 

 ears. The general colour of the animal is reddish brown or 

 rufous, but on the forehead of adult animals between the 

 ears and theeyes, and somewhat further forward, there is a w^ell 

 marked black area contrasting to the red body. The ears 

 are black, with more or less of the upper margin towards 

 the tip, and part of the tuft whitish. In young animals the 

 forehead is coloured like the body, only mixed with blackish. 



The general pattern exhibited by these two groups appears 

 to be constant within the group, with the exception to be 

 mentioned below, even if the general colouration varies rather 

 irregularly, especially in the P. cJioeropotamus-growp . There 

 are, however, several different geographic races within each 

 group and these races appear to be distinguished principally 

 by cranial cliaracteristics, and by their different size. To 

 make a comparison between the different cranial dimensions 

 of the different races the accompanying tables of measurements 

 have been prepared. 



Potamoclioerus porcus (Lin). 



It is evident that the cranial dimensions of such ani- 

 mals as the River Högs or Bush Pigs^ which continue to 

 grow for a long period extending through several years, must 

 be subjected to a considerable individual variation. There is 

 a considerable difference between males and females from the 

 some locality, as well as between younger and older males. 

 In this table of measurement (I) as in the following there 

 has been used some terms to signify the age of the indivi- 

 duals measured, viz. »semiad» (=semiadult) for animals in 



^ The official zoological name appears to be River Högs, but in Africa 

 these animals are mostly known as Bush Pigs, and from a biological point 

 of view this latter name is more suitable and will be mostly used in the 

 following. 



