50 COLUBRID.E. 



that in tlie 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 distinct from each 

 other, and connected only by ligaments. By this arrange- 

 ment not only is great dilatability of the mouth obtained, 

 which is also aided by a peculiarity in the structure of the 

 joint, but one side of either jaw is capable of acting inde- 

 pendently of the other ; and as the animal is gradually taking 

 its prey, one side of the jaws is extended forwards, and the 

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

 lower, fixed into the integument ; then the opposite 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 oesophagus, and by the muscular action of 

 this part it is swallowed. When a frog is in the progress of 

 being swallowed 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 disappears, the three 

 legs and the head are seen standing forwards out of the 

 Snake''s mouth in a very singular manner. Should the Snake, 

 however, have taken the Frog by the middle of the body, it 

 invariably turns it by several movements of the jaws, until 

 the head is directed towards the throat of the Snake, and 

 it is then swallowed head foremost. This process will remind 

 all who have w^itnessed the curious sight of the great Boa 

 taking its food, of the manner in which that enormous rep- 

 tile effects its deglutition, after it has, by the pressure of its 

 mighty sides, killed and crushed the bones of its victim. 



The scene above described is one which I have often wit- 

 nessed ; and I once saw two Snakes seize upon the same 

 hapless frog. As this circumstance is not unlikely to hap- 

 pen in their native state, it may not be out of place to men- 

 tion the result. On placing a frog in a large box, in which 

 were several Snakes, one of the latter instantly seized it by 



