338 CLASS REPTILIA. 



think that this name comes from the Brazilian word boa, 

 which is said to mean a serpent. 



Linnaeus was the first systematic writer who established 

 this genus. It was subsequently adopted in part by Lau- 

 renti, Boddaert, Daubenton, and Schneider. The ancients 

 appear to have had some acquaintance with some of its 

 species. Aristotle speaks of African serpents as long as 

 vessels by which a galley with three oars might have been 

 overturned. Pliny talks of Indian serpents capable of swal- 

 lowing deer. Elian mentions dragons of eighty to one hun- 

 dred cubits in length ; and finally, Suetonius mentions that 

 there was exhibited at Rome, under Augustus C^sar, a 

 living serpent of fifty cubits in length. 



The tortuous actions and enormous mviscular power of the 

 snakes result from an organization altogether their own, which 

 we shall illustrate by figures taken from the boa constricto7\ 

 The vertebra and the ribs constitute the entire skeleton of the 

 body, as they have neither sternum, pelvis, bones, or limbs. 

 Each vertebra has an apophysis on the upper side, which, in 

 the boa constrictor, is separated from that of the adjoining 

 vertebra, but in others, as the rattle-snake, these apophyses 

 seem to touch each other ; on the tail, however, of all these 

 animals, the upper apophyses become mere tubercles. Fig. 1, 

 will shew their shape and arrangement in the boa constrictor 

 — the articulation of the vertebras to each other is in an im- 

 bricated manner. The lateral or transverse apophyses are 

 articulated to the ribs by a ball and socket joint, in the man- 

 ner represented in the same figure. Thus the upper side of 

 the mobile vertebral column is furnished with a series of later- 

 ally flattened appendages to the vertebrae, separated and at 

 some distance from each other, evidently for the purpose of 

 preventing a dislocation of the vertebrte ensuing from the 

 animal inclining itself too much backward ; a partial capabi- 

 lity of such a movement is permitted by this arrangement, 



