344 SAVAGE SUDAN 



is found as far as Jebel Mokram, near Kassala, but 

 no farther, since exactly at that point it is replaced 

 by the Isabelline and Dorcas gazelles. Southward it 

 crosses the Settite but, somewhere in the neighbourhood 

 of Gallabat, gives way to the red-fronted gazelle. For 

 these details I am indebted to Bimbashi O'Callaghan, 

 of the Egyptian Army, for some time stationed at 

 Kassala, and my cabin-mate homewards in 1914. 



Elsewhere in this book are given several instances of 

 singularly interrupted distribution. Two curious examples 

 occur among the gazelle-tribe along the western bank of 

 White Nile. 



From El Dueim, a village on the White Nile 120 

 miles south of Khartoum, starts the old-time caravan- 

 route winding away across the deserts for 130 miles to El 

 Obeid. The traveller at first crosses a bush-clad riverain 

 belt of 15 miles in breadth, upon which strip all the 

 gazelles seen are red-fronted. But at that precisely 

 defined point the red-front stops dead ; and beyond it, 

 all the gazelles are Dorcas ! The latter species then 

 occupies by itself a stretch of 100 miles, across to a place 

 called Taweel, 115 miles west of Nile. Thereat the 

 Dorcas stops as abruptly as it began and the red-fronted 

 gazelle reappears. 



Each species restricts itself exclusively to its 

 own apportioned zone, and never are the two seen 

 intermingled. 



The second, and parallel instance, refers to the addra 

 gazelle, and by a curious coincidence occurs in precisely 

 the same region that is, in the deserts west of El 

 Dueim. 



Now to every big - game hunter in Sudan the 

 addra represents a prize ; but a prize not to be 

 gained save at a stiff price. To reach its desert-home 

 involves a long and wearisome trek by camelry into 

 Sahara save in the single isolated case about to be 

 mentioned. 



