42 THE STORY OF FISH LIFE. 



instances we find quite complex structures. In 

 the porcupine globe-fish (Diodon), for example, 

 the teeth are formed by the fusion of a series of 

 plates piled one above the other ; the lowermost 

 of this series, deep down in the jaw, are quite 

 separate, the uppermost touch one another, and 

 finally fuse into a solid mass. This form of 

 tooth is derived by modification of the order of 

 succession of which we shall speak presently on 

 p. 43. 



So far all the teeth which we have passed in 

 review have been attached to the jaw. But, 

 amongst the fishes, teeth are by no means 

 confined to this region. Thus, in the lung-fish 

 (Ceratodus), large teeth are found in the roof of 

 the mouth. In the higher bony fishes, such as 

 the pike, the palate is crowded with teeth; 

 and not only the palate, but even the gill-bars 

 are thickly set with teeth. The gill-teeth of 

 the sun-fish, for instance, are of extraordinary 

 size. 



Some fish, such as the roach and carp, have no 

 teeth in the jaws, but very large ones in the 

 throat. 



The nature of the attachment of the teeth is 

 quite worth a hurried notice. We need, how- 

 ever, only institute a few comparisons. "We 

 have already remarked that in the lowest fishes, 

 such as the sharks and dog-fishes, the teeth 

 rest upon, but are not firmly attached to, the 

 jaws. In the higher fishes the teeth have 

 acquired an intimate connection with the jaws, 

 often as complete as in ourselves. In some, 

 as in the angler-fish (Lophius) and the pike, the 



