xiv PREFACE 



constant racial characters. The giant eland inhabiting the 

 Lado Enclave and Bahr-el-Ghazal Province is a good ex- 

 ample of the case in point. The Nile race differs very 

 slightly from its geographical ally which is found, as far as 

 we know, only in the Senegal region on the West Coast of 

 Africa and is separated from the Nile form by some two 

 thousand miles. Although so widely isolated geographi- 

 cally from the Senegal eland, Taurotragus derbianus, the 

 degree of difference in coloration or other characters of the 

 Nile race is so slight that we prefer not to give it specific 

 rank, and refer to it merely as a race Taurotragus derbianus 

 gigas. 



Genera we have treated in a similar way; that is, we 

 have made degree of difference the essential feature and 

 have grouped together only species equally related. Con- 

 venience has not been considered a determining factor, no 

 account being taken of the number of species within the 

 genus. A few cases of antelope genera demanding segrega- 

 tion in order to emphasize the relationships of their various 

 species have come under our notice. Hunter's antelope of 

 the Tana River is a case of this sort. This species has been 

 taken out of the genus Damaliscus with which it neither 

 agrees in horn shape nor coloration and has been placed in a 

 new genus, Beatragus. The genus Kobus as generally used 

 is a further instance of a similar sort. Three groups of not 

 especially close relationship and all of wide distribution 

 over Africa have been associated together. This genus is 

 now split into: Kobus , the waterbucks of large size with 

 wide-spreading, slightly recurved horns and shaggy-haired 

 bodies; Adenota, the kobs of small size with s-shaped horns, 

 and short-haired bodies; and, finally, Onotragus, the lech- 



