48 MAEINE AND AQUATIC TRESPASSERS. 



in which the development of the teeth is extraordinary, 

 and, at present, unexplained. 



Both sexes have in youth a few teeth which soon 

 fall out, but in the upper-jaw of the male are two teeth 

 which are capable of enormous development. In the 

 female these teeth, or tusks, as they may be called, 

 remain, as a rule, undeveloped, and are not seen exter- 

 nally ; but in the male, one of them, usually the left, 

 is developed into a long horn-like tusk, sometimes 

 reaching to the length of ten feet, and containing an 

 enormous mass of ivory. 



The power of the animal may be inferred by lifting 

 one of these large horns, which, as the animal seldom 

 exceeds twelve or thirteen feet in length, is very nearly 

 as long as itself. The tusks are supposed to be develop- 

 ments of the canine teeth. They are smooth externally, 

 gradually tapering, and spirally grooved in so perfect 

 a manner that they seem to be beautifully carved in the 

 lathe. The ivory is of good quality. 



The question now arises, What can be the use of 

 the tusk, and how can it aid the animal in its course of 

 life ? This question is at present unsettled, and it is 

 not easy to frame any hypothesis which will account 

 for it. 



Some persons have thought that it was used in 

 order to pierce the fish on which it feeds, much after 

 the same manner that the saw-fish dashes among its 

 prey, and disables them with its tremendous beak before 

 seizing them in its mouth. If both sexes of the narwhal 

 were armed with the horn, as both sexes of the saw-fish 

 are armed with a beak, this theory might have some 

 grounds of probability. 



