ZOOLOGY — NAllWAL. 491 



foration up the centre, might be tusks of the right 

 side. Sir Everard Home, in his examination of the 

 tusks of the narwal, found, on sawing one, that ap- 

 peared solid, in a longitudinal direction, " a hollow 

 tube in the middle through the greater part of its 

 length, the point, and the portion at the root, only 

 being solid*. 



All the male narwals that I have at different 

 times seen killed, excepting one, had a tusk of 3 to 

 6 feet in length, projecting from the left side of the 

 head, of which about 8 inches in length of each, was 

 imbedded in the skull. The perforation, in all, ex- 

 tended from the base to wdthin 10 or 12 inches of 

 the small end of the tooth. 



The use of the tusk in narwals is ambiguous. 

 It cannot be essential for procuring their food, or 

 none of them would be without it : nor is it, per- 

 haps, necessary for their defence, else the females and 

 young would be subjected to the power of enemies 

 without the means of resistance, while the male 

 would be in possession of an admirable weapon for 

 its protection. Dr Barclay, with whom I have 

 communicated on this subject, is of opinion, that 

 the tusk is principally, if not solely, a sexual distinc- 

 tion, similar to what occurs among some other ani- 

 mals. Though it cannot be essential to the exis- 

 tence of the animal, it may, however, be occasional- 

 ly employed. From the extremity being smooth 



* PhU. Trans, for 1813. 



