500 



FLAT-FISH 



of the fishes. It is in consequence of having those 

 marginal iins along what appear from its position ii 

 the water the two sides of a fish of this kind, that th 

 name of Pleuronectes, or " swimmers by means o 

 the sides," was first given to those fishes by Artedi 

 This name is certainly founded upon the most re- 

 markable structural character of these fishes, ant 

 therefore it serves well enough for distinguishing 

 them from other fishes ; but if we are to consider the 

 side of a flat-fish as having the same position with 

 regard to the spinal column which the side of any 

 other fish has, then it is not by means of fins attached 

 to the sides, but by fins attached to the ridge of the 

 back and the middle of the belly, that those fishes 

 perform their principal motions in swimming. 



Flat-fishes have the head small, and also short, in 

 proportion to the whole volume of their bodies ; the 

 opening of their mouth is also small, and the teeth 

 very minute. Their gills are rather contracted, and 

 in many species the gill-lids consist of only a single 

 piece. There are six rays in the gills, but their 

 whole volume is small as compared with that of the 

 fish, so that their quantity of breathing must be limited. 

 The cavity of the body is very small and short, but 

 it is prolonged in small sinuses toward the tail. They 

 have no air bladder ; and, indeed, if we are to adopt 

 the common opinion, and suppose that this viscus has 

 anything to do with the change of specific gravity, 

 and consequent ascent and descent of the fish, we 

 might conclude that such an apparatus would be quite 

 superfluous in those fiat-fish, inasmuch as their most 

 powerful action in swimming is an ascending or a de- 

 scending one. They, however, do not avail them- 

 selves much of this, as they seldom rise far from the 

 bottom, and their motions, when they do rise, are very 

 slow and wriggling. They cannot, indeed, make much 

 way without so much flexure of the body, as exposes 

 a considerable portion of their white sides, and thus 

 renders them very conspicuous objects to those fishes 

 which prey upon them, and they are the chief food of 

 several species of the voracious cartilaginous fishes. 



In general they remain placidly on, or near the 

 bottom, sometimes with only a little portion of the 

 upper surface of the head exposed, and then their 

 colours on the upper part are generally so similar in 

 colour to sand and mud, that their enemies have some 

 difficulty in finding them out. Many of them are 

 very prolific : the spawn of the common flounder, for 

 instance, containing little short of a million and a half 

 of germs ; nor is it unworthy of remark that there ap- 

 pears to be in this class of fishes a considerable cor- 

 respondence between the powers of production, and 

 the absolute numbers and distribution. The sole, for 

 instance, which, though abundant in its localities, is a 

 much more local fish than the flounder, does not pro- 

 duce above a tenth of the progeny ; and this gives us 

 some reason for thinking that, though we are not in 

 possession of all the elements necessary for the full 

 establishment of the fact, there is a good deal of cor- 

 respondence between the productive power of fishes, 

 and their actual numbers. 



Nor can we fail to admire the great degree of con- 

 cealment which those fishes derive from their shape 

 and colour. When they are on the bottom, it is not 

 very easy for any other species of fish to see them or 

 to seize hold of them even if they should ; and they 

 themselves are, on the other hand, placed in the very 

 situation in which they can use their eyes with the 

 greatest possible advantage, both in finding their own 



food, and in escaping from becoming the food of their 

 more powerful neighbours. Their forms, their situa- 

 tion at the very bottom of the water, and all their 

 habits, cut them off from almost every means of safety 

 excepting concealment ; for they have less scope for 

 escaping, and are less fitted for availing themselves of 

 the scope they have, than any other race of fishes. 



From the character of the mouth, the smallness of 

 the teeth, and the fact of some of the species having 

 teeth only on one side of the mouth.it is evident that 

 flat-fishes are not capable of taking prey of any great 

 size. So also, from what has been said of the feeble- 

 ness of their powers of motion, it must be evident that 

 they are not adapted for giving chase to any animal 

 which can get away from them, with even a moderate 

 degree of speed. Still, the whole race are animal 

 feeders, and in proportion to the extent of their 

 powers, they are voracious, Indeed, fishes of all 

 kinds are great feeders ; and, though some feed upon 

 minute substances,and others swallow fishes, much more 

 nearly equal to their size than one would at first sight 

 be led to expect, yet they all feed more greedily, and 

 perhaps more largely than the majority of land ani- 

 mals. It is probable that the muscular powers of fishes 

 are much less subject to fatigue than those of land 

 animals ; and though they spend a good deal of their 

 time in a state of rest, either in the volume of the 

 waters, or at the bottom, it is doubtful whether any 

 of the species have a renovation by sleeping, at all 

 resembling that of land animals. From the slowness 

 of their motions, and the little range in distance which 

 they require to undergo, it is highly probable that the 

 flat-fishes have less muscular exertion than most others 

 of the class ; but as it is impossible to observe their 

 habits with any minuteness, nothing very positive can 

 be declared respecting them. In all probability their 

 chief food consists of those molluscous animals, and 

 minute fishes, which the tides and currents of the 

 bottom carry along, and deposit on the banks, and 

 other places where flat-fishes abound. That they do 

 not feed upon any sort of ground animal, but on some- 

 thing which floats in the water over them, is proved 

 by the position of their eyes, which are probably the 

 chief organs in guiding them to their food. They very 

 readily, however, take bait in small pieces, and though 

 most of them prefer molluscous animals, a little bit of 

 almost any fish will suffice. Those which ascend the 

 estuaries of trouting streams are often very annoyingly 

 deceiving to those who use bait in angling. The flat- 

 fish catches very readily at the bait, and as the form 

 and twisting up and down of its body, render it much 

 more difficult to pull through the water than any 

 common-shaped fish, the hope of possessing a trout 

 'our or five pounds in weight, changes into the actual 

 Dossession of a flounder of not the same number of 

 ounces. 



There are a few difficulties connected with the na- 

 ;ural history of flat-fish, as indeed there are with every 

 ish, and more especially with every fish which keeps 

 much below the surface. It seems too, that there are 

 sometimes peculiarities in individual specimens of 

 species which are well known, such as the head 

 wisted the other way, or the sides of nearly the same 

 :olour. But still the general characters of the family 

 are obvious and well marked, so that there is never 

 any risk of confounding any one of them with a fish 

 of any other kind. Considered as articles of food, 

 here is great difference, and this applies not only to 

 he quality, but to the quantity, ot eatable matter 



