83 GEOGRAPHICAL DISTRIBUTION. 



nearly nine -tenths of the latter being peculiar. The remaining 

 species are South American or Central American forms. In addi- 

 tion to this number there are some ninety or more migrants from 

 North America. 



THE ETHIOPIAN REALM. 



Next in importance to the Neotropical realm in the number, 

 variety, and peculiarity of its animal productions, is the Ethio- 

 pian, or African. This region comprises the entire continent of 

 Africa south of the Tropic of Cancer, and likewise that portion of 

 Arabia which lies to the south of the same line ; the Island of Mada- 

 gascar, with some neighbouring groups of smaller islands, is also 

 included. By some naturalists the northern boundary is extended 

 as far north as the Atlas Mountains, thus including the entire Desert 

 of Sahara. With the limitation first assigned almost the entire 

 region lies within the tropics, and is thus the most strictly tropical 

 of the faunal regions. In its physical features it presents several 

 well-marked peculiarities. In the first place, we have the vast 

 expanse of desert, which in the north occupies a transverse band 

 varying in width from about four to nearly ten degrees of latitude. 

 Tliis is succeeded by what may not improperly be termed the open 

 pasture-lands, which, as a narrow belt boimds the Sahara on the 

 south, curves southwards at about the position of Kordofan, and 

 occupies the greater portion of the continent lying east of the thir- 

 tieth parallel of east longitude and south of the fifth parallel of south 

 latitude. A very considerable portion of this pasture tract forms 

 a plateau of from four thousand to five thousand feet elevation. 

 Included within it, and bounded on the west by the Atlantic Ocean, 

 is the region of the great equatorial forests, to the present day a 

 terra incognita in great part to both geographers and naturalists. 

 That portion of the African continent lying south of the Tropic of 

 Capricorn differs in many respects, both as to its physical con- 

 figuration and its vegetable products, from the region to the north- 

 ward, and is characterised by a vegetation which is at the same 

 time one of the richest and most remarkable on the globe. With 

 this marked peculiarity in its vegetable development there is of 

 necessity a certain amount of faunal peculiarity superadded as well, 

 but this is not sufficiently pronounced to permit of a separation of 

 this tract from the tract lying immediately to the north. We have 



