SERPENTS. 151 



of hard cement, and penetrate the dorsal (upper) 

 parietes of the oesophagus : they may be readily 

 seen even in very young subjects, and in the 

 interior of that tube, in which their points are 

 directed backwards. The shell being sawed open 

 longitudinally by these vertebral teeth, the eg^ 

 is crushed by the contractions of the gullet, and 

 is carried to the stomach, where the shell is no 

 doubt soon dissolved by the gastric juice."* 



The tongue in this Order is slender, and di- 

 vided into two long and pointed filaments, which 

 are capable of being entirely retracted within a 

 sheath, or of being protruded from the mouth, 

 with great swiftness of motion. Serpents are said 

 to be enabled to lap up fluids with this forked 

 tongue, which, however, seems to be ill suited for 

 such an operation. -f- The vulgar notion which 

 associates a hurtful power with the tongue, 

 often spoken of as the " sting," is entirely er- 

 roneous. 



The mode in which respiration is performed is 

 described by MM. Dumeril and Bibron to be as 

 follows : — " The glottis, which has two lips, and 

 represents a very simple larynx, opens in the 

 mouth beneath the sheath of the-, tongue ; by 

 means of the muscles of the os hyoides [or bone 

 of the tongue], which push it, it is raised so as to 

 be presented in a dilated state behind the back 

 nostrils. The vacuum caused by the action of the 

 ribs in the belly tends to dilate the lung, which 

 through the medium of the trachea, immediately 

 admits the air which is introduced during an 

 inspiration : this is slow, continuing for some 



* Odontography. 



't' Our European Snakes drink by suction, not by lapping. 



