FORM AND PECULIARITIES 
superiority in his external senses ; and we accordingly 
find, that he enjoys a more perfect organ of hearing, in 
having an external opening of considerable size for the 
purpose of conveying sounds to the internal ear more 
readily and acutely than could be done through the dense 
and thick integument, which is continued over the 
auricular opening in the northern whale. 
Although the eyes in both animals are very small in 
comparison with their bulk, yet it is remarked that they 
are tolerably quick -sighted. I am not aware that the 
sperm whale possesses in this respect any superiority. 
Passing to the mouth, we again observe a very re- 
markable difference in the conformation of the two ani- 
mals ; as in place of the enormous plates of whalebone 
which are found attached to the upper jaw of the Green- 
land whale, we in the sperm whale only find depressions 
for the reception of the teeth of the lower jaw; organs 
which again are totally wanting in the other. Corre- 
sponding with these distinctions, which plainly point out 
that the food of the two whales must be very different, 
we find a remarkable difference in the size of the gullet. 
The several humps, or ridges, on the back of the 
sperm whale constitute another difference in their external 
aspect; these prominences are however not altogether 
peculiar to the sperm whale, as that which is called by 
whalers the “humpback^ possesses a prominence on 
the back not very dissimilar to that of the sperm whale, 
which has been noticed before in the introductory re- 
marks, and which induced Lacapedd to divide the genus 
Balsena into those with a hump, and those without; 
