TEETH AND FOOD 



29 



in order to facilitate the entrance of the prey; at the same 

 time, however, as they cannot be pressed in the opposite 

 direction, they effectively prevent any chance of escape. 

 Similar depressible teeth are found in the Angler-fish or Fishing 

 Frog {Lophius), and in many of the deep-sea forms, such as the 

 Ceratioid Anglers, Wide-mouths (Stomiatoidea) , Gulpers {Lyo- 

 meri), etc., which habitually seize and devour fishes larger 

 than themselves (Figs. 31, 91). In a few of these creatures the 

 teeth are even luminous, although the advantage to the fish in 

 thus exhibiting its formidable dentition is a Kttle doubtful. 

 The Pike is almost unsurpassed in greediness and ferocity, and 



Fig. 54. — PHARYNGEAL TEETH. 



A. Ventral view of skull and dorsal view of hyo-branchial skeleton and lower jaw 



of Wrasse {Labrus sp.), showing position of pharyngeal bones, X ^ ; b. Vertical 



section of skull of Bow-fin (Amia calva), showing position of pharyngeals, X 4 ; 



c. Lower pharyngeals of Carp {Cypnniis carpio), x ^. 



when on the feed nothing comes amiss to its insatiable maw. 

 It has been estimated that a Pike will consume in a single day 

 its own weight of food, so great is its appetite and so rapid its 

 digestion. Fishes are its normal diet, and these are seized 

 crosswise and swallowed head first. Its method of feeding is to 

 lurk within a clump of vegetation, or to He motionless in the 

 water looking like a moss-covered log. As soon as a victim 

 comes within reach he is overwhelmed with a sudden rush and 

 disappears in a smother of foam. Water-birds, frogs, and voles 

 are also devoured, and instances are on record of human beings 

 being attacked by hungry Pike. Cases of cannibalism are by no 

 means rare, the Pike being one of the few fishes which will 



