OF a^HE DEGLUTITION. 59 



ceive the eggs, is enlarged and tenuinated by a fringed 

 border at its anterior end ; this canal descends straight 

 towards the anus, and terminates by a wide opening in the 

 bottom of the cloaca, below the valve which separates that 

 cavity from the rectum. 



The testicles, of a variable fonn in diffei-ent species of 

 Ophidians, are of a deeper colour than the kidneys. The 

 vasa dcferentia go out from the internal surface of the tes- 

 ticles ; in making numerous little turns, they descend along 

 the external edge of the kidneys, and are adherent through 

 their whole extent to the ureters ; approximating on the 

 back of the cloaca^ they perforate the walls common to this 

 cavity and the ureters, and open into the mouths of these 

 last, which are indicated, as we have already stated, by a 

 conical elevation. The mouths of the vasa deferentia are 

 so delicate that they are only perceptible in serpents of a 

 large size, — ^a circumstance which renders anatomical re- 

 searches very difficult, because Ave can neither inflate the* 

 organs, nor pass a probe, on accomit of theu' convoluted 

 structure. 



OF THE DEGLITTITIOJSr. 



The manner in which snakes swallow their food is very 

 simple. They always commence at the head of their prey, 

 which they receive into their mouth • while the teeth fasten 

 themselves on one side of their prey to hold it fast, the op- 

 posite jaw advances, and the teeth engage themselves in 

 the victim, and draw it inwards. By this alternate play of 

 the jaws, during ivhich the principal part is performed by 

 the lower jaw, the deglutition is effected, after efforts more 

 or less great according to the volume of the prey. It is 

 also for the same object that the jaws dilate, in order to 

 render the swallow more capacious : during this act, the 

 serjDcnt discharges an abundant saliva on its prey, Avliich it 

 renders more slippery, and more easy to be swallowed. 

 AYhen the animal they attempt to swallow is too large, they 

 are unable to introduce it into their maw until a consider- 

 able time has elapsed. Serpents found in this state offer 

 a hideous spectacle ; the disgust which they thus inspire, 



