•378 Mr. Hunter’s Obfervntions on the 
is larger than in quadrupeds, having more the propor- 
tion obferved in fifh, and (welling out laterally at the 
articulation of the lower jaw : this may probably be for 
the better catching their prey, as they have no motion of 
the head on the body ; and this didance between the arti- 
culations of the jaw is fomewhat fimilar to the Sw r allow, 
Goat- fucker, Bat, &c. which may alfo be accounted for, 
from their catching their food in the fame manner as fifh ; and 
this is rendered dill more probable, fince the form of the 
mouth varies according as they have or have not teeth. There 
is, however, in the Whale tribe more variety in the form of the 
head than of any other part, as in the Whalebone, Bottle- 
nofe, and Spermaceti Whales ; though in this lad it appears 
to owe its (hape, in fome fort, to the vad quantity of fpermaceti 
lodged there, and not to be formed merely for the catching of its 
prey. From the mod$ of their progredive motion, they have 
not the connexion between the head and body, that is called 
the neck, as that would have produced an inequality inconve- 
nient to progredive motion. 
The body behind the fins or (houlders diminiflies gradually 
to the fpreading of the tail ; but the part beyond the open- 
ing of the anus is to be confidered as tail, although to ap- 
pearance it is a continuation of the body. The body itfelf is 
flattened laterally ; and, I believe, the back is much (harper 
than the belly. 
The projecting part, or tail, contains the power that pro- 
duces progredive motion, and moves the broad termination, 
the motion of which is fimilar to that of an oar in (bulling a 
boat; it fuperledes the necedity of poderior extremities, and 
allows of the proper (hape for fwimming; that the form may 
be preferved as much as poflible, we find that all the projecting 
6 parts. 
