Dr. J. Kirk un the Birds of the Zambesi Region. 311 



strange affinities to other continents, and foreshadowing what is 

 yet to come from the unknown centre of Southern Tropical Africa. 

 The difficulties which now stand in the way are those of transport 

 in parts where horses cannot live, and through the coast-region, 

 in which alone there is any great danger from the people. In 

 the interior, with a knowledge of the language and a little good 

 management, there is little fear. But great patience is required, 

 and the deadly river-valleys must be avoided. 



Few regions of equal extent present so uniform a type in their 

 organic beings as Tropical Africa. In its birds this is especially 

 noticeable, most of the species being common to both sides of the 

 continent. Placed between the Cape and Abyssinia, the Zambesi 

 contains a few species peculiar to each. 



In its animals the Cape offers no such marked differences as 

 we find in the plants. These constitute one of the best marked of 

 botanical regions, characterized both by many and singular ende- 

 mic species, and by the high development of natural groups else- 

 where weakly represented. They may represent an ancient flora 

 now cut off from all communication with other temperate forms 

 by the tropical zone of Africa, which, having no lofty axial range, 

 is as effectual a barrier to the transmission of plants as if it had 

 been an ocean. Although the present geological features of Cen- 

 tral Africa are of great antiquity, a difference of climate must 

 have prevailed when the great inland seas existed, and a change in 

 its organisms have taken place when these were drained through 

 lateral fissures. The formation of river-deltas would commence 

 at that time. Fossils contained in these parts attest the existence 

 of species of animals identical with the present — probably soon 

 after they began to be formed; while the absence of these 

 species from the island of Madagascar would indicate that a 

 separation between it and the mainland has taken place before 

 the present fauna occupied the continent. 



As that island contains very many plants of the peculiar Cape 

 types, we may look on these as representing an age or flora 

 anterior to the separation, allowing for modifications which 

 may have since taken place under altered conditions. But, quite 

 independently of this, we find another element in Madagascar 

 and its neighbouring islands, the Mascarenes, Comoros, and 



