THE TEETH OF FISHES. 235 



and size in all parts of the mouth. As a general rule, fish 

 do not comminute their food very fully, but make use of 

 their teeth simply for the apprehension of prey, not sub- 

 mitting the food to any mastication whatever ; their teeth 

 are hence often mere sharp cones, slightly recurved, or set 

 looking backwards. Thus, though the mouth of the common 

 pike is beset with an immense number of sharp teeth, its 

 food is swallowed whole, and very often is alive when it 

 reaches the stomach, the sole purpose served by the teeth 

 being the prevention of its escape when once it has been 

 seized. 



Implantation of the teeth in sockets is not usual in the 

 class of fish, but it does occur : for example the Barracuda 

 pike (Sphyrasna) has its lancet-shaped teeth implanted in 

 distinct sockets, to the walls of which they are said to 

 become slightly anchylosed; the file-fish and others might 

 also be cited. And although the succession of teeth is 

 usually from the side, in some cases the successional teeth 

 are developed in alveolar cavities within the substance of 

 the bone, and displace their predecessors in a vertical direc- 

 tion, as happens in the pharyngeal teeth of the Wrasses, or 

 the curiously human-looking incisors of the Sheep's-head fish 

 (Sargus) ; the Lepidosteus also has its teeth affixed in incom- 

 plete sockets, to the walls of which they are anchylosed ; 

 this is not a very uncommon arrangement with the teeth of 

 fish when they are socketed at all. 



The teeth of fish are of all degrees of size and of fineness ; 

 in some (Chsetodonts) the teeth are as fine as hairs, and are 

 so soft as to be flexible. 



Teeth which are very fine and very closely set are termed 

 "dents en velours;" when they are a little stouter, " dents 

 en brosse," and when still stronger and sharper, "dents en 

 cardes." Teeth that are conical, wedge-shaped, spheroidal, 

 and lamelliform, are all to be met with ; in fact there is 

 infinite diversity in the form of fishes' teeth. 



