THE DESERT CLIMATE 3 



after the winter rain, and southwards by savanna, 

 that is to say, arid grass land with a few trees. 

 The largest of all deserts is practically continuous 

 from the Atlantic coast of North Africa to North- 

 west India and the heart of China. It includes 

 the whole of Northern Africa down to about lati- 

 tude 20° N., but excluding those parts of Morocco, 

 Algeria, and Tunisia which border the Mediterranean : 

 it includes also Egypt and Sinai ; Arabia, the 

 Syrian Desert, and Mesopotamia ; Persia, Afghani- 

 stan, and Baluchistan ; Transcaspia, Turkestan, and 

 the Gobi Desert, in Central China ; and parts of 

 the Punjab, Sind, and Rajputana. The whole of 

 this vast area is inhabited by the same types of 

 animals and plants, and these for the most part 

 are derived from Europe and Northern Asia, and 

 to a much smaller extent from equatorial Africa 

 or peninsular India. The great desert is, in fact, 

 an integral part of the " Palsearctic Region," which 

 is one of the primary divisions into which zoolo- 

 gists and botanists have divided the globe : this 

 region includes all Europe, and Northern and 

 Western Asia, and Africa as far south as the southern 

 part of the Sahara (about latitude 20° N.). I pro- 

 pose, therefore, to use the term " Great Palsearctic 

 Desert " when referring to this tract. 



The great desert of Australia is probably the 

 second in the world in point of size ; it includes 

 the heart of the continent and reaches nearly to 

 the west and south-west coasts. 



The North American deserts consist of several 

 small areas in the southern and south-western 



