CHAPTER XI. 
THE ETHIOPIAN REGION. 
THIS is one of the best defined of the great zoological regions, 
consisting of tropical and South Africa, to which must be added 
tropical Arabia, Madagascar, and a few other islands, all popu- 
larly known as African. Some naturalists would extend the 
region northwards to the Atlas Mountains and include the whole 
of the Sahara; but the anima] life of the northern part of that 
great desert seems more akin to the Palearctic fauna of North 
Africa. The Sahara is really a debatable land which has been 
peopled from both regions; and until we know more of the natural 
history of the great plateaus which rise like islands in the waste 
of sand, it will be safer to make the provisional boundary line at 
or near the tropic, thus giving the northern half to the Palearctic, 
the southern to the Ethiopian region. The same line may be 
. continued across Arabia. 
With our present imperfect knowledge of the interior of 
Africa, only three great continental sub-regions can be well de- 
fined. The open pasture lands of interior tropical Africa are 
wonderfully uniform in their productions; a great number of 
species ranging from Senegal to Abyssinia and thence to the 
Zambesi, while almost all the commoner African genera extend 
over the whole of this area. Almost all this extensive tract of 
country is a moderately elevated plateau, with a hot and dry 
climate, and characterised by a grassy vegetation interspersed 
with patches of forest. This forms our first or East African 
sub-region. The whole of the west coast from the south side of 
the Gambia River to about 10° or 12° south latitude, is a very 
