FISHES. 
11 
Herring and Pilchard for example, have similar 
thread-like branches sent off from each of the 
vertehrcE ; so that the bodies of these fishes seem 
filled with long and slender bones. 
The skull varies much in form in different 
tribes, but in general consists of pieces answering 
to those which compose the head of the other 
Vertebrata. Teeth are generally very numer- 
ous ; and are found in almost every one of the 
bones that enter into the composition of the 
mouth, though not in all the species. They are 
generally simple spines, curved backwards, but 
innumerable modifications of this form occur. 
Thus the jaws of the deadly Shark are flat and 
lancet-like, the cutting edges being notched like 
a saw ; the front teeth of the Flounder are com- 
pressed plates ; some, as the Wrasse, have flat 
grinding teeth; others, as the Sheep’s-head, have 
the grinding surface convex ; and others, as the 
genus ChrysopJirys^ have convex teeth so numer- 
ous and so closely packed over a broad surface, 
as to resemble the paving-stones of a street. The 
beautiful Chaetodons of warm climates, on the 
other hand, have teeth which resemble bristles, 
and these are set close together like the hairs of 
a brush ; while the Perch of our own rivers have 
them still more slender, minute and numerous, 
so as to resemble the pile of velvet. Another of 
our well-known fishes, the bold and fierce Pike, 
is armed with teeth scarcely less formidable in 
size, form, and sharpness, than the canines of 
a carnivorous quadruped. In number also there 
is great variety. The Pike, the Perch, the Cat- 
fish, and many others, have their mouth crowded 
with innumerable teeth, while the Carp and the 
