8b 



THE FOOD OF ANIMALS 



supposed to be capable of emitting a phosphorescent light. This 

 curious modification of the red-worm-like bait of the common 

 shallow-water angler into a will-o'-the-wisp lantern, attracting 



little fishes to their destruc- 

 tion in the deadly jaws of the 

 Melanocetus, is one of the 

 most interesting adaptations 

 that has been brought to light 

 by our study of the deep-water 

 fauna. " 



Crushing Teeth. — Many 

 bony fishes feed upon mol- 

 luscs, hard-shelled Crustacea,, 

 and other creatures which 

 require crushing before they 

 can be digested, and in these 

 forms the teeth, or some of 

 them, are converted into firm 

 plates suitable for mastication. 

 Such teeth are present in 

 the Wrasses, shallow - water 

 species which feed on crusta- 

 ceans, molluscs, and in some 

 cases on corals. Many of 

 these fishes are provided with a strong, curved upper tooth at 

 each angle of the mouth, the use of these being to hold the food 

 in position between the crushing front and side teeth. Attention 

 may also be called to the voracious Wolf-Fishes {Anarrhichas), 

 gigantic members of the Blenny Family, which inhabit the 

 northern parts of the great oceans. In these creatures not only 

 are the margins of the jaws provided with strong blunt teeth, 

 but there is also a longitudinal band of similar teeth on the palate. 

 Electric Organs. — Certain fishes are provided with electric 

 organs, with which they are believed to kill or stun their prey, 

 and which have been produced by modification of some of the 

 muscles (fig. 368). Those belonging to the group now under 

 consideration are inhabitants of fresh water. They include the 

 Electric Cat- Fishes of tropical Africa and the Electric- Eel from 

 tropical South America. The last may be as much as 6 feet in 

 length. 



Fig. 367. — Deep-sea Angler [Melanocetus Murrayi) 



