38 AFRICAN GAME ANIMALS 



the distribution of animals and are the most precise means 

 of defining their ranges. 



Extending along the coast from Lamu southward is a 

 narrow strip of country which is well characterized by the 

 groves of cocoa-palms which grow luxuriantly on the low 

 coral coast plain and the hill country inland to an altitude 

 of five hundred feet. This stretch of low country may be 

 known as the tropical coast zone. It receives consider- 

 ably more rainfall than the dry desert country flanking it, 

 and supports a luxuriant vegetation during the short rainy 

 season, but is semiarid in character, with little semblance 

 of tropical luxuriance. The cocoa-palm marks the zone 

 precisely, extending from the seashore inland to the sum- 

 mits of the low coast hills. 



On the Uganda Railway the zone extends from Mom- 

 basa to Mazeras, having a width here of fifteen miles. 

 Farther north it narrows down to a few miles in width, 

 owing to the coast hills approaching the coast and confining 

 the coastal plain. At the Tana River it broadens again and 

 extends up the alluvial valley a score of miles. Still far- 

 ther north beyond Lamu it gives way entirely to the desert, 

 which here reaches the seashore. Several plant associa- 

 tions are found within the zone. A mangrove association 

 composed largely of three species of mangroves, Rhizo- 

 phora mucronatay Bruguiera gymnorrhiza, and Avicennia 

 officinalis^ occupies much of the territory about the inlets 

 and the tidal portions of streams. Forests occur in places 

 on the slopes and crests of the coast hills. They are quite 

 dense assemblages of a variety of trees, chief among which 

 is the giant Trachylobium hornemannianum, a wide-spread- 

 ing, white-barked tree. Other common forest-trees are 



