200 ox THE GEOGRAPHICAL 



tirely similar, and often also absolutely identical with 

 those of Malacca, of Bengal, of India, and even of Cey- 

 lon. Sometimes, however, the species in those different 

 places present differences more or less marked, and give 

 rise to the establishment of local varieties. To judge 

 from the small number of its productions known to us, 

 the great Island of Madagascar would appear to have a 

 Fauna of its own. Africa is not rich in Ophidians. The 

 southern part of that vast peninsula produces species dif- 

 ferent from those of Europe, or of other parts of the earth ; 

 and those same species are often found dispersed over 

 intertropical Africa, and even extending to the northern 

 parts of that continent ; but besides a few peculiar species, 

 those last countries produce several others, which inhabit, 

 at the same time, almost all the countries bordering on the 

 Mediterranean, even Syria, and consequently a gi^eat part of 

 Europe. Most of the serpents of this last continent, finally, 

 are spread over a gi'cat part of temperate Asia, — a region 

 which appears to produce but a small number of peculiar 

 species. 



The geographic distribution of genera or of families, 

 viewed as representing the different principal forms, is not 

 a less curious study, than that of the species. We see at 

 once that the venomous snakes are distributed, perhaps, 

 with the exception of some islands, in every country in- 

 habited by snakes in general. These dangerous reptiles ap- 

 pear not to dread cold, for they are found often as far to 

 the north as the innocuous species. But their number is 

 much more limited than that of the latter : for if we 

 reckon the number of all known Ophidians at 263, 57 of 

 these are venomous,* which makes the proportion of the 

 venomous to the innocuous as 1 to 5. We shall see, 

 however, afterwards, that this proportion is not the same 

 in all countries of the globe, and that the number of 

 venomous serpents, at least that of indi\'iduals, appears 

 to be more considerable in naked and steril countries, 



* We should also remark, that seven species of venomous snakes ex- 

 clusively inhabit the ocean^ where non-venomous serpents are never 

 seen. 



