STUDY OF REPTILES 117 



Owen said, " can outswim the fish, outleap the zebra, outwrestle 

 the athlete, and crush the tiger." 



To understand the matter clearly it is necessary to have 

 a snake's skeleton. A set-up specimen will last for many years 

 if it is carefully enclosed in a long box with a glass lid and a glass 

 floor so that both sides can be seen. Delicate skeletal specimens 

 should always be sealed up. Whenever it comes to touching the 

 bones in demonstration the specimen's days are numbered. 

 On the other hand, it is useful to have some stout snake's 

 vertebrae threaded on a wire. It is then an easy matter to 

 demonstrate, for instance, the highly developed ball-and-socket 

 articulations. 



3. Snakes are given to tackling prey which seems much too 

 large for the size of their mouth. Thus it seems at first almost 

 ridiculous that a grass snake should attempt to swallow a frog. 

 In connection with this habit we find that the two halves of 

 the lower jaw are not united in front except by ligament, and 

 that many bones of the skull, e.g. of the upper jaw and palatal 

 regions, are loosely attached to one another, though there is, 

 of course, a rigid box protecting the brain. 



If we watch a grass snake swallowing a frog a sight best 

 reserved for private edification we see that it grips its victim 

 so that the head is swallowed first ; it moves forward the right 

 half of the lower jaw, gripping with the left ; it takes a new grip 

 with the right half, and advances the left ; it thus laboriously 

 draws itself over the frog. The distent ion of the gullet region 

 is almost as extraordinary as that of the mouth. The long wind- 

 pipe, opens far forward in the mouth, and the glottis can be 

 protruded a little between the tips of the lower jaw, so that the 

 snake is not suffocated by its extraordinary swallowing. It 

 need hardly be said that the popular impression that snakes 

 lubricate their prey by covering them with saliva before they 

 swallow them has as little foundation as most popular impres- 

 sions. The grain of truth in the notion is that internal salivation 

 helps the booty down. 



4. In poisonous snakes some of the teeth have a groove down 

 the front side, or a canal formed by the closure of a groove, 

 and down this groove or canal the poison passes into the wound 



