CHAP. IV.] zoolo:jical regions. 73 



Etliiopiaii Ixegion. — The limits of tliis region have been indi- 

 cated by the definition of the Palsearctic region. Besides Africa 

 south of the tropic of Cancer, and its islands, it comprises the 

 southern half of Arabia. 



This region has been said to be identical in the main charac- 

 ters of its mammalian fauna with the Oriental region, and has 

 therefore been united with it by Mr. A. Murray. Most impor- 

 tant differences have however been overlooked, as the followinir 

 summary of the peculiarities of the Ethiopian region will, I 

 think, show. 



It possesses 22 peculiar families of vertebrates ; 90 peculiar 

 genera of mammalia, being two-thirds of its whole number ; 

 and 179 peculiar genera of birds, being three-fifths of all it 

 possesses. It is further characterized by the absence of several 

 families and genera which range over the whole northern 

 hemisphere, details of which will be found in the chapter 

 treating of the region. There are, it is true, many points 

 of resemblance, not to be wondered at between two tropical 

 regions in the same hemisphere, and which have evidently been 

 at one time more nearly connected, both by intervening lands 

 and by a different condition of the lands that even now connect 

 them. But these resemblances only render the differences more 

 remarkable ; since they show that there has been an ancient and 

 long-continued separation of the two regions, developing a dis- 

 tinct fauna in each, and establishing marked specialities which 

 the temporary intercommunication and immigration has not 

 sufficed to rem.ove. The entire absence of such wide-spread 

 groups as bears and deer, from a country many parts of which 

 are well adapted to them, and in close proximity to regions 

 where they abound, would alone mark out the Ethiopian region 

 as one of the primary divisions of the earth, even if it possessed 

 a less number than it actually does of peculiar family and 

 generic groups. 



Suh-divisions of the Ethiopian Region. — The African conti- 

 nent south of the tropic of Cancer is more homogeneous in its 

 prominent and superficial zoological features than most of the 

 other regions, but there are nevertheless important and deep- 



