THE FLAT-FISH FAMILY. 



THE three chief peculiarities of the flat-fishes are (i) 

 that the two eyes are on one side of the body, (2) that 

 the upper or eyed side is coloured, the lower side white, (3) 

 that the dorsal fin extends forwards as far as or beyond the 

 eyes, but along the edge of the head, not between the eyes. It 

 is not difficult, if a flat-fish such as a plaice and an ordinary fish 

 such as a haddock are examined together, to see what the real 

 differences are, though probably few who handle flat-fishes daily 

 in the course of business ever trouble to make the comparison. 

 Fishermen, however, are accustomed to distinguish between left- 

 handed and right-handed flat-fishes, and in doing this they place 

 the edge on which the mouth and belly are, towards themselves, as 

 one naturally does in looking at one of these fishes. On this 

 edge also are the gills, while on the other is the brain. It is 

 easily seen that apart from the eyes and colour the upper side and 

 lower side are very much alike, and are really left side and right 

 side. There is a gill-flap on each side, and a breast-fin and a throat- 

 fin. It follows therefore that the two fins which run along the 

 edges of the body are the dorsal or back fin, and the ventral or 

 belly fin, corresponding to those of the ling or tusk. In a tur- 

 bot or halibut it will be seen that the two sides of the mouth are 

 almost exactly alike in size and shape, so that the peculiarity of 

 the eyes of a flat-fish does not necessarily make the mouth lop- 

 sided. In fact the position of the eyes is due entirely to a 

 twisting of the part of the face containing the eyes, to a bending 

 round of the bridge of the nose, which brings the right eye on to 

 the left side or the left one to the right side as the case may be. 

 The front part of the dorsal fin is on the side of the face, there- 

 fore, separating the eye nearest to it from its proper side of the 

 head. In certain flat-fishes, especially the turbot, specimens are 



