10 
SHARKS. 
dition. A number of vascular fibres are provided, which hang 
from the orifices of the breathing holes, and even from the 
temporal orifices where these are provided; and they do not 
disappear until the creature is prepared for its permanent state 
of existence. It is a remarkable instance of the accuracy with 
which the transitory condition of interuterine existence is pro- 
vided for, that the whole of the contents of the nittrient bag 
forming the egg has become absorbed into the body at the very 
instant when its presence is no longer required, and the fish 
has become capable of seeking its own support. 
It may be mentioned as a piece of superstition, that in no 
very distant times the teeth of Sharks, under the name of ser- 
pent’s teeth, were set in silver, and used to render more easy 
the cutting of the teeth in children. It was more in reference 
to their supposed occult virtue, than to their mechanic effect, 
that even so wise a man as the physician and naturalist Kondele- 
tius believed that when reduced to powder they formed also 
an excellent tooth powder. 
SHARKS, 
These are fishes of a lengthened form, having the mouth 
and nostrils placed under a projecting snout, the jaws furnished 
with several rows of teeth, the gill-covers bound down to the 
side, and the openings like separate slits in the skin, not less 
than five in number. The fins covered with the common skin, 
the tail irregularly lobed, the upper portion being of greater 
length than the lower, and having the vertebras, or joints of 
the back, carried onward close to the border of the caudal fin. 
There are some kindred species, which vary in some degree 
from the shape most common in this family, by approaching 
more nearly to that of the Rays; on which account they are 
said to be aberrant. Of these we shall take notice when 
describing such of them as have been taken on the British 
coasts. 
The following arrangement of such of the genera of this family 
as belong to the catalogue of British fishes, is derived from the 
“Animal Kingdom” of lihe Baron Cuvier, but modified in a 
few particulars, by the observations of the German naturalists 
Midler and Henle, and by Dr. Gray. 
