9 8 INTRODUCTION 



crushed by constriction, very much exceed the 

 calibre of the snake. A Python molurus 17 feet long 

 is reported on good evidence to have swallowed a 

 gravid Axis deer. A Grass-snake half an inch in 

 diameter can manage a frog or toad three times 

 that width, and a Dasypeltis of the same size a hen's 

 egg. Such feats are rendered possible by the 

 mobility of the jaws and palato-pterygoid arch on 

 the cranium, and the elasticity of the ligaments by 

 which they are attached (see above, p. 42), as well 

 as by the mobility of the ribs and the absence of 

 sternal apparatus, together with the great dis- 

 tensibility of the skin. When a snake proceeds to 

 dispose of a large prey, which, if it be a mammal or 

 bird, is usually seized head-first, it pulls itself 

 forward by alternate movements of the jaws, the 

 maxillary and the mandibular ramus of the one side, 

 and then of the other, being extended anteriorly and 

 laterally, the snake at the same time producing an 

 abundant salivation which renders the prey very 

 slimy. Several repeated alternate movements of the 

 jaws bring the head of the prey to the gullet, where 

 the muscles and ribs come into play, and the two 

 sides of the jaws work no longer alternately, but 

 together. When once in the oesophagus, the prey 

 progresses with much greater facility, and usually 

 reaches the stomach in a few minutes, whilst the 

 previous process of deglutition may have lasted half 

 an hour. While this laborious operation is going 



