DISTRIBUTION OP OrillDIANS. 215 



graphic distribution of serpents in that quarter of the 

 workl, and still less to assign to each species the precise 

 limits which determine the habitats which Nature has 

 assigned to each ; not knoAving in an exact manner, so 

 to speak, more than the productions of the three or four 

 principalpoints*of this continent which have been explored, 

 we find ourselves constrained to limit our indications of 

 species, and of the places where they have been observed. 

 Africa is, in general, much less rich in reptiles, and notably 

 in serpents, than Asia and America. The number of 

 genera is equally circumscribed in that continent ; but 

 we find among reptiles the same phenomena which are 

 observed in the other animals and plants of that part of 

 the world ; namely, that the species of certain genera are 

 extremel}^ numerous, and that these different species often 

 inhabit the same places : a fact which applies also, though 

 less extensively, to New Holland. These are, in general, 

 animals inhabiting plains, the number of species of which 

 is multiplied in Africa. It is thus we see at the southern 

 extremity of that continent three or four species of Land 

 Tortoise, four species of serpents of the genus Coronella, 

 as many of the genus Naja, and three of the genus Vipera. 

 The other genera of serpents there produced, have only 

 a single species to represent them. These snakes, almost 

 without exception, pertain to species peculiar to that con- 

 tinent. Some are found on the coast of Guinea ; such as 

 the Lycodon of Horstock, and the Naja rhombeata : the 

 Psammophis moniliger is also found there ; but it forms a 

 local variety approaching to that inhabiting Egypt. In Se- 

 negambia, three species of Tree- Snakes of the genus Den- 

 drophis are found, different from those of the Cape, one 

 of which, D. picta, is spread over a great part of Asia, 

 even to New Gruinea. The intertropical regions of Africa 

 support the Two-rayed Python, the native country of Avhich 

 extends even to China, and the Island of Java. The 

 Lancing Viper of the Cape, Vipera arietans, is also found 

 in Abyssinia, where it forms a local variety with pale 



* Egypt as far as Abyssinia, Algeria, one part of Senegambia, and of 

 the coast of Guinea, the Cape Good Hope. 



