OPHIDIA. 59 



cies attain a length of thirty or forty feet, preying on dogs, deer, 

 and even oxen, which they manage to swallow entire, after having 

 crushed them in their folds and covered them with saliva. This 

 operation requires much time and an enormous dilatation of their 

 jaws and throat. Their small lung is but half the length of the 

 other. 



The integuments of the head and jaws of these serpents furnish 

 materials for a still further subdivision. 



1. In some the head down to the tip of the muzzle is covered with 

 small scales similar to those on the body, and the plates on the jaws 

 are not pitted. Such is the 



Boa constrictor^ L; Le Devin, Lacep. II, xvi, 1; Seb. I, xxxvi, 

 5, liii, 11, Ixxxviii, 5, xcix, 1, ci: Devin or Boa cmpereur of 

 Daudin.(l) Known by a broad chain, whi^ extends along the 

 back, formed alternately by large, blackish, irregularly hexa- 

 gonal spots, and by pale oval ones, the two ends of which are 

 emarginate. 



2. In others there are scaly plates from the eyes to the end of 

 the muzzle, but no fossuls on the jaws. 



Boa scytale and murina, L. ; Anaconda, Seb. II, xxiii, 1, and 

 xxix, 1; B. aquatica, Pr. Max. liv. II. Brown; a double suit of 

 round black spots along the back^ ocellated spots on the flanks. 



3. Some have scaly plates on the muzzle, and little pits or fossulse 

 on the lateral plates of the jaws. 



Boa cenchris, h. ; Moma and Porte Jinneau, Daud.; Seb. I, Ivi, 

 4, II, xxviii, 2, and xcviiij Boa cenchrya, Pr. Max. liv. VI. 

 Fawn coloured with a suite of large brown rings along the back, 

 and variable spots on the flanks. 



These three species, which attain a nearly equal size, inhabit 

 the marshy grounds of the hot parts of South Americaj winding 

 their tail round some aquatic tree, they dart their floating body 

 upon the quadrupeds which come there to drink. 



4. Some have plates on the muzzle, the side of the jaw being 



(1) Daudin thinks that the Devin is to be found in the eastern continent, but it 

 is certainly from Guiana. Vaillant and Humboldt have procured it there. Pr. 

 Max. has found it in Brazil. The two succeeding species were also brought from 

 Surinam bv M. Le Vaillant, and it is well known that the Bojohi inhabits Brazil. I 

 do not think there is any large Boa, properly so styled, in tlie eastern world. The 

 great Serpents of Africa and India are Pythons. The name Devin arises from the 

 circumstance of having improperly applied to this Serpent wliatis stated respect- 

 ing certain large Colubers, which constitute the Fetiches of some negro tribes. 



