50 VERTEBRATA. REPTILIA. 



place, the frog, in most instances, ceases to make 

 any struggle or attempt to escape. The whole body 

 and the legs are stretched out, as it were, convul- 

 sively ; and the Snake gradually draws in first the leg 

 he has seized, and afterwards the rest of the animal, 

 portion after portion, by means of the peculiar me- 

 chanism of the jaws, so admirably adapted for this 

 purpose. It must be recollected, that, in the true 

 Serpents, unlike the group to which the Slow-worm 

 belongs, the bones of which the upper and lower 

 jaw are composed are perfectly and loosely dis- 

 tinct from each other, and connected only by lig- 

 aments." By this arrangement, not only is the 

 mouth capable of being greatly expanded, but " one 

 side of either jaw is capable of acting independently 

 of the other ; and as the animal is gradually taking 

 its prey, one side of the jaw is extended forwards, 

 and the two rows of teeth of the upper and the single 

 row of the lower fixed into the skin ; then the oppo- 

 site side of the jaws is stretched forwards in the same 

 manner, and so on alternately until the victim is thus 

 gradually and often slowly conveyed into the gullet, 

 and by the muscular action of this part it is swal- 

 lowed. When a frog is in the process of being swal- 

 lowed in this manner, as soon as the Snake's jaws 

 have reached the body, the other hinder leg becomes 

 turned forwards; and as the body gradually disap- 

 pears, the three legs and the head are seen standing 

 forwards out of the Snake's mouth in a very sin- 

 gular manner. * * 

 " The scene above described is one which I have 



