208 
ON THE OEOaEAPHICAL 
Greece our Slow-worm has the body sprinkled with dark 
points, and is then the Anguis 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 earth which furnishes such striking proofs of the re- 
lations which subsist between animals and the places they 
inhabit. In studying, then, the constitution of that great 
continent, 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 sand, 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 atmosphere, 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 fresh 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 
