ANATOMY OF THE NAItWAL. 139 
i:i tliis animal much curved. Where it is fixed 
to the body, it is elliptical, the longest axis lying 
longitudinally; so that when the fin is elevated 
to its swimming position, it is horizontal. The 
point, or tip, is bent upwards, or towards the 
back; the fin, in a swimming posture, is conse¬ 
quently concave above, and convex below. The 
thick edge is forward; the thin edge towards the 
tail. The use of the fin, being horizontal, in 
swimming, is evidently to balance the animal; 
while the tail is the chief organ of motion, and is 
also used in turning. That the fins are not ge¬ 
nerally used for either swimming or turning, ap¬ 
peared probable, from several observations made 
on these animals with a telescope from the mast¬ 
head. The fins were always seen steadily ex¬ 
tended ; and when the animal changed its direc¬ 
tion, the tail was bent suddenly and obliquely to 
one side, and then slowly returned back, in such 
a way, that a progressive motion and a change of 
direction were produced by the same effort: the 
fins mean time were motionless. In the mysti- 
cctus, however, where the fin is much larger in 
proportion than in the narwal, it may have other 
uses. In all animals of the whale tribe, the fins 
must be employed in turning to one side, or on 
the back. 
r I lie blowhole is one external semilunar open- 
