the vast plains of the Siadan. Here short to tall grasslands are 

 dotted with scattered trees that are often thorny acacias and in 

 southern latitudes include various broadleaf species. Although 

 including much of West Africa beyond approximately 5°N.*, both of 

 these Districts are faunistically an extension of the East and 

 South African Subregion. 



West African faunal elements in the Sudan are confined 

 largely to Bahr EL Ghazal Province, Bquatoria Province west of 

 the Nile, and isolated populations in and about the bases of 

 mountain masses in eastern Equatoria Province. This fauna, in 

 the Ubangi-Uelle Savannah District, reaches southwestern Sudan 

 from central Nigeria. Isolated from that of the more open sa- 

 vannahs of East African Districts, this fauna is composed of 

 numerous genera, species, and subspecies not found in East Afri- 

 ca.^ It is a peripheral, grassier extension of the West African 

 (Guinean) Forest Districts that in the Sudan are represented by 

 only a few limited forests in Bquatoria Province. 



In southern Sudan, Equatoria Province east of the Nile and 

 southern Upper Nile Province support populations of animals 

 typical of the East African Highland District. Open, grassy 

 plains, with scattered thorn trees and with broad leaf trees 

 around termite mounds and beside rivers, carry to its northern 

 limit the magnificient plains fauna for which East Africa is 

 famed. In general, these animals differ at least subspecifi_ 

 cally from their relatives west of the Nile, althoiigh there is 

 some interdigitation of East African elements into the western 

 and northern Districts bordering the East African Highland. 



Eastward, the effect of the Abyssinian Highland District 

 is expressed in poorly explored outlying hills just within 

 the Sudan frontier. 



The Red Sea coast and the eastern slopes of the Red Sea 

 Hills, by reason of higher relative humidity and nxjre rainfall 

 than surroimding areas, carrj the fauna of the Somali Arid Dis- 

 trict northward at least to Port Sudan. 



*See modification of this latitudinal zonation for the Sudan, 

 page 8/^. 



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