6 
SHARKS AND RAY-FTSHES. 
at acute angles. The muscles themselves have a resemblance to 
those of quadrupeds, and the bundles of fibres which constitute 
their substance appear to possess the powers of separate action, 
by which the motions of the fish may be more minutely and 
effectually regulated. Such muscles as lie behind the ventral 
fins are accompanied with what may be denominated tendons, 
which are a portion of animal structure that does not exist in 
the common class of bony fishes; and by the use of these, which 
are longer and stouter the nearer they approach the tail, that 
important organ is enabled to put forth its very powerful action 
without being itself inconveniently stout. Although the lateral 
muscles of a fish’s body may be said to be innumerable, there is 
some propriety in considering those of the body of a Shark as 
forming four of large size, over and above those which are smaller 
and subordinate; for the tendino-cellular membrane interposed 
between the skin and muscle passes between those larger masses 
of muscle, and may be said either to divide or unite them, and 
at the same time serving to give firmness to their action by the 
general support it aflJ'ords them. This description is more es- 
pecially taken from the Eay-mouthed Dogfish and Toper {Mmtelus 
Imis and Galeus vzilgaris;) but with some variation it is, doubtless, 
observable in all Sharks. But it is more distinctly marked in 
the former species than in the latter, thus directing our views 
to Its importance; and accordingly it has been observed by 
fishermen that the former fish, when it has taken the hook, is 
much^ stronger in the water than the latter. 
It IS on account of the particular structure of the muscular 
la5^ers in Sharks that they are able to direct their motions with 
greater precision than the generality of fishes, and also that they 
can continue their efforts without weariness for an almost unlimited 
duration of time; and accordingly sailors inform us of the vast 
extent of ocean along which they have been accompanied by 
some of those fishes, without apparent weariness, when their 
appetites or expectations have been excited after prey. 
We shall defer the description of the eye of the Hays until 
we come to speak particularly of that tribe of fishes; but this 
organ is but little less curious in the Sharks, although its structure 
is founded on very simple principles as compared with that of 
other_ animals. In most kinds of fishes the eyes are round and 
prominent, without the possibility of being closed, even in sleep 
