DERIVATION OF THE FAUNA 25 



C — Present Distribution 



The big-game fauna of British East Africa and Uganda 

 is made up of three elements, or rather has been derived 

 from three different faunal areas. The chief source of this 

 derivation has been the South African region, to which 

 three-fourths of the species are closely alHed. A consider- 

 able number are closely allied to Somaliland or northeast 

 African species, while a very few, chiefly forest animals, have 

 been derived from the Congo region. The large carnivo- 

 rous mammals and the elephants are so generally distrib- 

 uted that there is little faunal significance to their dis- 

 tribution. The faunal divisions recognized are on this 

 account based upon the hoofed mammals solely. 



The region may be divided into two large faunal areas 

 which coincide with the two important drainage areas. 

 The greater of these in area and number of species is the 

 coast and Rift Valley drainage; the smaller, the Nile 

 watershed. The Rift Valley, though consisting of numer- 

 ous small independent lake-drainage systems is closely 

 allied faunally to the coast area, from which it differs by 

 almost no peculiarity. The real faunal barrier is west of 

 the Rift Valley, at the meeting of the Nile watershed and 

 these independent systems. Throughout the region this 

 barrier is marked by high mountains and plateaux. The 

 coast and Rift Valley drainage area is characterized in its 

 upper or highland portion by rolling, grassy plains flanked 

 on their higher parts by the forests which clothe the moun- 

 tain ranges of the district. On the lower borders the grassy 

 plains merge gradually into the dry scrub of the thorn- 

 bush deserts of the lowlands. In the immediate vicinity 



