EAST OF THE NILE. 401 Latika, and extending as far south as Usdga, may be compared 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 (Hyphene thebaica) reaches its southern limit at 5° 20’ 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, Leptadenia 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 Lquus zebra and #. Burchell, there are antelopes, giraffes, various kinds of hares, Lycaon pictus, of Hdentata, 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 Bér 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, 2C