9G ON THE rnYSIOGNOMY OP SERPENTS. 



We must reckon in the first rank of all known serpents, in 

 respect to its dimensions, the Boa murina, a native of the 

 equatorial re^ons of America. The Python bivittatus, 

 spread over intertropical Africa and Asia, is in the ancient 

 continent the representative of that Boa, and attains nearly 

 the same size. It is now found that the Python Schneideri, 

 inhabiting India, has an elongated shape, and rarely sur- 

 passes fifteen feet in total length ; the Boa Constrictor of 

 the New World joins to an inferior length a very consider- 

 able tliickness ; as also do several other Boas, Colubri, &c. 

 In our climate, serpents are rarely more than five feet in 

 length, but in middle Europe there is one species of Colu- 

 ber whicli arrives at the length of eight feet.* 



HABITUDES. 



Ophidians are spread over every country where tlie 

 conditions necessary to the existence of reptiles in general 

 are found. Every person knows that these cold-blooded 

 animals love heat ; that their number diminishes for this 

 reason in proportion as we approach temperate or frigid 

 regions ; and that they prefer, on that same account, banks 

 exposed to the heat of the sun, to elevated situations, or 

 places covered "vvith a thick and abundant vegetation. Yet 

 there are, even with us, species common in the plains, which 

 at the same time frequent the slopes of mountains, even at 

 the height of several thousand feet above the level of the 

 sea. Many Tropidonoti in Java abound on the solitary 

 peaks of the numerous extinct volcanoes, with w^hich that 

 island is bristled. But by far the greatest number of 

 Ophidians inhabit low lands, either naked or bosky, dry or 

 humid, and marshy. Some are only seen in the vast sandy 

 plains of the old continent ; j;he analogous deserts of both 

 Americas, known under the names of Pampas, Llanos, or 

 Savanas, are peopled by other species, often spread over 

 a vast extent of that continent. A gi'eat number of ser- 

 pents frequent shady places, and often even occur in the 

 thickest forests, sometimes concealed under luxuriant herbage 



* Coluber quaterradiatu.'^, the Boa of the ancient Romans. 



