208 ON THE GEOGRAPHICAL 



Greece our Slow-worm lias the body sprinkled with dark 

 points, and is then the Angiiis punctatissima of Bibron. 

 Finally, I could cite a great number of analogous facts 

 drawn from the class of Insects ; but this would lead me 

 into an abyss, through which I might never be able to see 

 my way. 



The study of the geographic distribution of animals in 

 Africa offers a number of facts extremely curious, and of 

 the highest importance to physical geography, and even to 

 descriptive zoology. There is not, perhaps, a country on 

 the eartli wliich furnishes such striking proofs of the re- 

 lations which subsist between aninuils and the places they 

 iuliabit. In studying, then, the constitution of that gi'eat 

 conthient, we may, in some degree, divine the nature of its 

 productions. The predominant feature of Africa is the 

 presence of vast arid plains ; whether they form true 

 deserts of yand, or present them under the aspect of ter- 

 raced table lands, elevated sometimes to a height of several 

 thousand feet above the level of the sea, and decked with 

 vegetation only during a short period of the year. A soil 

 of that nature, perpetually scorched by rays of a vertical 

 sun, is ill adapted to furnish vapour, which, condensing in 

 the atmosj^here. may again fall in rain, snow, or hail, to fer- 

 tilize the earth. These conditions, and the absence of lofty 

 mountains in that part of Africa, modify the nature of its 

 fresh waters, or of its streams in general. Hence, the 

 rivers of that continent are in all respects inferior to those 

 of other continents ; they but rarely form the grand ac- 

 cumulations of fresli water, which are so favourable to the 

 formation of vapours ; their banks are not usually covered 

 by that luxuriant vegetation which attracts such multi- 

 tudes of all classes of animals ; those rivers, swollen in 

 the rainy season, during a short period, by the sudden in- 

 crease of their waters, retire after this period within their 

 beds, where they are sometimes so much reduced as 

 scarcely to merit the name of a stream or a river. It re- 

 sults from what we have said, that Africa, being neither 

 watered by large rivers, nor covered with an abundant ve- 

 getation, being denuded of great forests, ought to support 

 but a small number of those animals that inhabit fresh 



