DENTAL SYSTEM OF FISHES. 243 



The anterior diverging grappling teeth of the wolf-fish 

 (Fig. 61), ?', form stronger cones ; and by progressive 

 blunting, flattening, and expai:^on of the apex, observ- 

 able in different fishes, the cone gradually changes to the 

 thick and short cylinder, such as is seen in the back teeth 

 of the wolf-fish, ?7z, and in similar grinding and crnshing 

 teeth in other genera, whether the fishes be feeders on 

 sea- weeds, or on crustaceous and testaceous animals. The 

 grinding surface of these short cylindrical teeth may be 

 convex, as in the sheep's-head fish (Sargus); or flattened, 

 as in the pharyngeal teeth of the wrasse {Labriis). Some- 

 times the hemispheric teeth are so numerous, and spread 

 over so broad a surface, as to resemble a pavement, as in 

 the pharyngeal bones of the wrasse ; or they may be so 

 small, as well as numerous, as to give a granulated sur- 

 face to the part of the mouth to which they are attached, 

 when they are called, in ichthyology, denies graniformes. 



A progressive increase of the transverse over the ver- 

 tical diameter may be traced in the molar teeth of differ- 

 ent fishes, and sometimes in those of the same individual, 

 as in hhrus, until the cylindrical form is exchanged for 

 that of the depressed plate. Such dental plates {denies 

 lamelliformes) may be formed not only circular, but ellip- 

 tical, oval, semilunar, sigmoid, oblong, or even square, 

 hexagonal, pentagonal, or triangular; and the grinding 

 surface may present various and beautiful kinds of sculp- 

 turing. The broadest and thinnest lamelliform teeth are 

 those that form the complex grinding tubercle of the 

 diodon. 



In the sharks and rays, the teeth are supported by the 

 upper and lower jaws, as in most quadrupeds; but many 

 other fishes have teeth growing from the roof of the 

 mouth, from the surface of the tongue, from the bony 



