i Structure and O economy of Whales. 403 
The whole furface refembles the (kin of an animal covered 
with ftrong hair, under which furface the tongue muff imme- 
diately lie, when the mouth is (hut ; it is of a light-brown 
colour in the Piked Whale, and is darker in the large. 
Whale. 
In the Piked Whale, when the mouth is fhut, the projecting 
whalebone remains entirely on the infide of the lower jaw, the 
two jaws meeting every where along their furface ; but how this 
is effected in the large Whale I do not certainly know, the hori- 
zontal plane made by the lower jaw being ftraight, as in the 
Piked Whale; but the upper jaw being an arch cannot be hid 
by the lower. 1 fuppofe, therefore, that a broad upper lip, 
meeting as low as the lower jaw, covers the whole of the outer 
edges of the exterior rows. 
The whalebone is continually wearing down, and renewing 
in the fame proportion, except when the animal is growing it 
is renewed fafter, and in proportion to the growth. 
The formation of the whalebone is extremely curious, 
being in one refpeCt fimilar to that of the hair, horns, fpurs, 
&c, ; but it has befides another mode of growth and decay, 
equally lingular. 
Thefe plates form upon a thin vafcular fubftance, not im- 
mediately adhering to the jaw-bone; but having a more denfe 
fubftance between, which is alfo vafcular. This fubftance, 
which may be called the nidus of the whalebone, fends out 
(the above) thin broad proceffes, anfwering to each plate, on. 
which the plate is formed, as the Cock’s fpur or the Bull’s 
horn, on the bony core, or a tooth on its pulp ; fo that each 
plate is neceffarily hollow at its growing end, the firft part of: 
the growth taking place 011 the infide of this hollow. 
Befides 
