TEETH OF HAIRTAIL. 201 



jaw fits into a niche in the lower jaw, so that when the 

 fish is going through the water the pecuHar shape of 

 the two jaws will not obstruct its progress. Upon the 

 extreme end of the upper jaw are four teeth, recurved 

 and not unlike a snake's fangs in general appearance. 

 The tips of these teeth are transparent, and, what is 

 exceedingly curious, I find these tips are barbed on their 

 posterior aspect like a fish-hook. When the mouth is 

 shut, these teetli fit into a cavity in the lower jaw, 

 and the tongue is prevented from being injured by 

 their sharp points by means of a valve of skin, which 

 is stretched across from side to side of the lower jaw, 

 and then runs upwards ; so that the top of the tongue is 

 really encased in a convenient guard, not at all unlike 

 a finger-stall made of an old glove, as applied to the 

 finger of a human hand. On the mystache, or superior 

 maxillary, there are a considerable number of very 

 sharp lancet-like teetli on each side. They remind me 

 very much of the shape of the teeth of the leech. 



The lower jaw also contains similar teeth which are 

 larger towards the angle of the mouth than towards 

 the symphasis or junctions of the arms of the lower 

 jaw. In fact the whole of the dental apparatus of this 

 fish is of a most formidable character. 

 ^ These terrible cutting (and I might almost say pre- 

 hensile) teeth are about a quarter of an inch long ; the 

 general form of the teeth would give it great swimming 

 velocity. I cannot, therefore, help thinking this fish is 

 one of the enemies of some small kinds of migratory fish, 

 such as anchovies, for a more beautiful living machinery 

 for catching these small and active fish could not pos- 

 sibly be devised. 



