INTROB UCTION. 215 



divide the country hypsometrically into four regions, 

 thus : — 



1. Subalpine region, 'above 9,000 feet.^ 



2. Temperate region, about 6,000 to 9,000 feet. 



3. Subtropical, about 3,000 to 6,000 feet. 



4. Tropical, below 3,000 feet. 



The altitudes are merely approximate, and vary some- 

 what in dififerent localities. Some animals range through- 

 out several regions : thus the Hamadryas monkey, spotted 

 hygena, wart-hog, and elephant amongst mammals, and 

 Neophron percnopterus, the Lammergeyer, the Common 

 Kite, Aquila rapax, Bucorvus abi/ssinicus, Pycnonotus 

 arsinoe, Corvus scapulatus, Buphaga erythrorhyncha, 

 Numida ptilorhyncha, and many migratory birds, are all 

 found throughout the three lower regions, and some of 

 them even in the subalpine zone. Some animals migrate 

 with the season, ascending to the highlands during the 

 summer and returning to the lower elevations in winter. 

 Others, such as Laniarius wthiopicus, Coracias abyssi- 

 nica, Corvus affinis, LamprocoUus chalybceus, though 

 usually confined to the subtropical and temperate regions, 

 are occasionally seen in considerable numbers near the 

 coast. 



The majority, both of the mammals and of the birds, 

 range into more than one of the regions indicated, but 

 still in passing from one to the other a very great and 



1 There may possibly be a still higher or Alpine region on the summits of 

 the Samyen mountains, close to the limits of perpetual snow. On a few of the 

 very highest peaks the snow is said never to disappear entirely. 



