154 
GREENLAND VOYAGEi 
perhaps, by the epiglottis), that enables the animal 
under the immense pressure to which it is some¬ 
times exposed, to exclude the sea-water from its 
lungs. This pressure, at some depths to which the 
whale has been known to descend, is upwards of a 
ton upon every square inch ; yet, so far from the 
water being forced down the canals or spiracles, 
the enormous load serves only more effectually to 
press down and close the valves, that defend the 
passages to the lungs. 
The whale has no external ear ; and the open¬ 
ing of the passage to this organ is so small, 
as not to be easily discovered. In the sucking 
whale, it was only one-sixth of an inch in diame¬ 
ter. An elegant contrivance appears in the me¬ 
atus auditorius extcrnus, for protecting the ear 
against pressure from without. It consists of a 
little plug, like the end of the finger, inserted in 
a corresponding cavity in the midst of the canal, 
by a slight motion of which the opening can ei¬ 
ther be effectually shut, for the exclusion of the 
sea-water, or unclosed for the admission of sound. 
In the sucking-whale, the skull or crown-bone 
was six feet in length, from the anterior extremi¬ 
ty to the condyles. In a full grown animal, in 
which the whalebone was 10 feet 4 inches, the 
length of the skull, measured along the upper 
and convex side of the curve, was 20 feet 8 in- 
