EAST OF THE NILE. 401 



Latuka, and extending as far south as Usoga, may be com- 

 pared to certain tracts of Kordofan which contain scattered, 

 bare mountain groups, sandy steppes, reservoirs of water, and 

 a nomadic population. 



Following the configuration of the country, the limits of 

 certain forms of vegetation run here much farther to the south 

 than they do to the west of the river or in the river-valley itself. 

 In the latter, for instance, the dum palm (Hyphcene thebaica) 

 reaches its southern limit at 5 2 c/ N. lat., while in Latuka I 

 have seen woods of it, and then it has been found following a 

 large curve to the south-east. In the east, also, a Lawsonia is 

 common, which I could not distinguish from Lawsonia inermis* 

 also Calotropis procera, Zeptadenia pyrotechnica. and on the 

 margins of rain-torrents a tamarisk — all of them trees which 

 do not appear at all in our country proper, or, like Calotropis, 

 but seldom. 



While the plants just mentioned suffice to determine the 

 botanical status of the country, its fauna also is peculiar to 

 itself. Besides Uqicus zebra and E. Burchellii, there are 

 antelopes, giraffes, various kinds of hares, Lycaon pidus, of 

 Edentata, Orycteropus, and Manis, of monkeys, Theropithecus, 

 and a species, perhaps new, of Cercopithecus, which give the 

 country a character of its own. With the exception of the 

 monkeys, which are, of course, restricted to the forest, whether 

 open steppe forest or connected woodlands, they are all true 

 inhabitants of the steppe, and therefore on the western bank 

 of the Bahr-el-Jebel they appear only in the flat country 

 as far as the skirts of the mountains, but entirely avoid their 

 slopes. The extraordinary abundance of elephants in the 

 east may be connected partly with the occurrence of forests 

 of Balanites, but, on the other hand, considering the scanty 

 supplies of water towards the east, may be due to the fact that 

 the animal is capable of long marches, and in the dry season 

 retires to the broad swamps of the Ber country, which never 

 dry up, and to the swamps on the northern frontier of Usoga, 

 where he defies all pursuit. What is true of the Mammalia 

 must, of course, also hold good of the birds, and we must next 



* A fact of great importance as regards the origin of this widespread object of 

 cultivation. — G-. S. 



2 C 



