OF THE SPERM WHALE, 
31 
employing the name Balaena for the latter, and styling 
the others Balaenoptera. 
I have before adverted to the sharp cutwater-like 
conformation of the under part of the head in the sperm 
whale, and it is worthy of remark that the same part of 
the Greenland whale is nearly, if not altogether, flat. 
The skin of the sperm whale, as of all other cetaceous 
animals, is without scales, smooth, but occasionally, in 
old whales, wrinkled, and frequently marked on the 
sides by linear impressions, appearing as if rubbed 
against some angular body. The colour of the skin, 
over the greatest part of its extent, is very dark, most so 
on the upper part of the head, the back, and on the 
flukes, in which situation it is in fact sometimes black, 
on the sides it gradually assumes a lighter tint, till on 
the breast it becomes silvery grey . 
In different individuals there is, however, considerable 
variety of shade, and some are even piebald. Old 
“ bulls,” as full-grown males are called by whalers, have 
generally a portion of grey on the nose immediately 
above the fore-part of the upper-jaw, and they are then 
said to be “ grey-headed.” 
In young whales the “ black skin,” as it is called, is 
about three-eighths of an inch thick, but in old ones it 
is not more than one-eighth. 
Immediately beneath the black skin is the blubber or 
fat, which is contained in a cellular membrane, and 
which is much strengthened by numerous interlacements 
of ligamentous fibres, which has induced Professor Jacob 
to consider the whole thickness of blubber to be the cutis 
