162 WATER REPTILES OF THE PAST AND PRESENT 



land lizards. If they preyed upon small animals only, or if they 

 tore their prey to pieces after the manner of the alligators, there 

 would have been no especial difficulty in deglutition. But it is 

 certain that the animals which the mosasaurs devoured were not 

 always small, and they must have been swallowed whole, since their 

 teeth were not adapted, like those of the alligators and true croco- 

 diles, for the rending of bodies. One who has watched a snake swal- 

 low a frog or another snake will appreciate the difficulties against 

 which the mosasaurs contended in swallowing fishes a fifth or a 

 sixth of the length of their own bodies. The ordinary snake, no 

 matter where or how it seizes its prey, invariably swallows it 

 head first. Its mandibles are even more loosely united in front 

 than were those of the mosasaurs, and while there is no joint in 

 the snake's mandibles such as there is in the mosasaurs', the loose 

 union of the various bones of the mandibles serves the same purpose. 

 The frog or lizard, while firmly held by the slender teeth, is slowly 

 moved sideways by the alternate lateral action of the jaws till 

 the head is reached. Many non-poisonous snakes, if they find it 

 impracticable or impossible to reverse the position of their prey 

 in this way, wrap the folds of their body about it, holding it firmly 

 while they release their mouth-hold and seize it by the head. 

 An amusing instance of these habits came under the observation 

 of the writer not long ago, in Texas. A large "blue racer" (Bas- 

 canion), six feet four inches in length, caught an unusually large 

 bullfrog by one hind leg, but in almost less time than it takes to 

 relate, the head of the frog had entered the snake's gullet and the 

 mouth was closed over it, notwithstanding the vigorous muscular 

 and vocal protests on the part of the frog. Wishing to secure 

 the skull of the snake for his collection, the writer seized an ax 

 standing conveniently by and cut the snake cleanly in two. The 

 peristaltic action of the deglutitional muscles carried the frog 

 slowly on about two feet farther to the ax-made orifice, from 

 which it emerged, and, after a few croakings against such unkind 

 usage, calmly hopped off into the near-by pool of water! Many 

 poisonous snakes release their prey after killing it; other snakes 

 may force their prey down the throat by pressing it against 

 the ground. 



