60 ON TUE PHYSIOGNOMY OF SERPENTS. 



augmented by the mephitic odour which the prey, already 

 attacked by putrefaction, exhales, has given rise to nume- 

 rous fables of which the poets have taken advantage. De- 

 glutition takes place in the same manner in all serpents, 

 not excepting the venomous snakes, who, in this operation, 

 depress their fangs, and conceal them in the sheath of the 

 gums, in order to defend them from injury. 



or THE DIGESTION. 



The digestion goes on but slowly, notwithstanding the 

 activity of the gastric juice of serpents. It appears, how- 

 ever, that this fluid is only secreted in abundance by that 

 portion of the stonuich near the pylorus ; for the animals 

 which are taken out of the stomach of snakes are always 

 decomposed at the lower portions, whilst the parts near the 

 oesophagus do not exhibit the slightest trace of putrefaction. 

 I have verified this fact, discovered by M. Lenz,* in a great 

 number of exotic species. In captivity, serpents reject by 

 the mouth indigestible substances, such as feathers, hairs, 

 &c. This faculty is common to them with most birds. 



When a serpent is pursued that has swallowed its food, 

 it often disgorges it, in order to escape more quickly.t 

 This fact is also observed in many birds. J 



OF THE ORGANS OF CIRCULATION. 



The heart of Ophidians has generally an elongated form, 

 and is noted for its being placed far from the head. It is 

 sometunes found at the distance of the first third of the 

 length of the trunk. We find it with large auricles sepa- 

 rated from each other by a membranous septum : the ven- 

 tricle, on the other hand, is imperfectly divided into two 

 narrow cavities, by a partition derived from the base of the 



* See for the deglutition of snakes, Researches of M. Duges, inserted 

 in the Ann. de Sciences Nat., 1827, xii. p. 362. 



* P. 48. 



t Note communicated by M. Dieperink at Paramaribo. See also 

 Lenz, I. c. 



:J: The Stercorea, the Gull, and the Sea-swallow, &c. 



