108 



FISH GALLERY. 



are then seized by them and swallowed. They feed also largely on 



cuttle-tishes. 



Fig. 95. 



L 

 Lower view of head of Saw-fish. 



The Rhinobatidoe (Case 43) contain the genera Rhynchobatus, 

 Rhinobatus, and Trygonorhina. A fine series of Rhynchobatus 

 ancylostomus, with preparations of its curious dentition, is exhibited 

 iu a separate case in the middle of the Gallery. They feed on 

 hard-shelled animals, and attain scarcely, a length of 8 feet. They 

 are confined to the coasts of tropical and subtropical seas^ 



The Torpedinida, or Electric Rays (Case 42). — The electric 

 organs with which these fishes are armed are large, flat bodies 

 lying one on each side of the head ; they consist of an assemblage 

 of vertical hexagonal prisms, whose ends are in contact with 

 the integuments above and below. The fish gives the electric 



