ZOOLOGY.— ^NARWAL. 489 



middle. The upper side of the tail is also blackish 

 round the edges : but in the middle, grey, with 

 black curvilinear streaks on a white ground, form- 

 ing semicircular figures on each lobe. The under 

 parts of the fins and tail are similar to the upper, 

 only much paler-coloured ; the middle of the fins 

 being white, and of the tail a pale-grey. The co- 

 lour of the sucklings is almost wholly a bluish-grey, 

 or slate-colour. 



The integuments are similar to those of the mys- 

 ticetus, only thinner. The cuticle is about the 

 thickness of paper : the rete mucosum three-eighths 

 to three-tenths of an inch thick ; the cutis thin, but 

 strong and compact on the outer side. 



A long prominent tusk, with which some nar- 

 wals are furnished, is considered as a horn by the 

 whale-fishers; and as such, has given occasion for 

 the name of Unicorn being applied to this animal. 

 This tusk occurs on the left side of the head, and 

 is sometimes found of the length of 9 or 10 feet ; 

 according to Egede, 14 or 15* It springs from the 

 lower part of the upper-jaw, points forward and a 

 little downward ; being parallel in its direction to 

 the roof of the mouth. It is spirally striated from 

 right to left ; is nearly straight, and tapers to a 

 round blunt point ; is of a yellowish-white colour, 

 and consists of a compact kind of ivory. It is usu- 

 ally hollow from the base to within a few inches of 



• " Description of Greenland/' p. 77. 



