HOW ANIMALS EAT 275 



Deglutition in the serpents is painfully slow, and 

 somewhat peculiar. For how is an animal, without 

 limbs or molars, to swallow its prey, which is often 

 much larger than its own body ? The boa constrictor, 

 e.g., seizes the head of its victim with its sharp, recurv- 

 ing teeth, and crushes the, body with its overlapping 

 coils. Then, slowly uncoiling, and covering the carcass 



FIG. 235. Skull of Boa Constrictor: i, frontal; 2, prefrontal; 4, postfrontal; 5, basi- 

 occipital; 6, sphenoid; 7, parietal; 12, squamosal; 13, prob'tic; 17, premaxillary; 

 18, maxillary; 20, nasal; 24, transverse; 25, internal pterygoid; 34, dentary, lower 

 jaw; 35, angular; 36, articular; a, quadrate; s, prenasal; v, petrosal. 



with a slimy mucus, it thrusts the head into its mouth 

 by main force, the mouth stretching marvelously, the 

 skull being loosely put together. One jaw is then un- 

 fixed, and the teeth withdrawn by being pushed forward, 

 when they are again fastened farther back upon the 

 animal. The other jaw is then protruded and refas- 

 tened ; and thus, by successive movements, the prey is 

 slowly and spirally drawn into the wide gullet. 



