Flat-fishes 



645 



Photo by W. Saville-Kent, F.Z.S.] 



[Milford-on-Sea. 



As in the turbot, the eyes are oil the left side of the head, instead of on the right side, as in the 



halibut. 



a mirror at the bottom the 

 iinder-surface was found in 

 many cases to be very largely 

 coloured. But the colour of 

 the upper-surface is by no 

 means constant. On the con- 

 trary, the flat-fish appears to 

 possess the power, in common 

 with all other fishes, of chang- 

 ing its colour so as to harmon- 

 ise with the tone of its sur- 

 roundings. Thus on a light 

 sandy ground the exposed 

 surface of the body becomes 

 pale, while on a dark muddy 

 bottom it is almost black. 

 By this power of changing 

 the colour of the exposed 

 portion of the body so as to 

 harmonise with the surround- 

 ings, the fish is enabled to 

 become in a large measure 

 invisible, and in proportion 

 to the effectiveness of the change to escape its enemies. Some soles are quite invisible. 



The most important of the flat-fishes are the PLAICE, FLOUNDER, DAB, HALIBUT, SOLE, 

 TURBOT, and BRILL. 



The PLAICE is one of the commonest of the British flat-fishes, and may be distinguished 

 by the numerous orange or red spots which are scattered over the upper surface of the body. 

 From 15 to 18 inches in length, specimens are occasionally captured which have attained a 

 length of 28 inches. Plaice feed on shell-fish, such as mussels or scallops, which they crush 

 by means of strong, blunt teeth in the throat ; but worms are also eaten. 



The eggs of the plaice are amongst the largest fish-eggs known. 



The FLOUNDER is a smaller fish than the plaice, and lacks the red spots. It differs from 

 the other flat-fishes in the preference it shows for the mouths of rivers, ascending these, 

 indeed, so far as to enter fresh-water. 



The HALIBUT is the largest of the flat-fishes, specimens of as much as 20 feet in length being 

 on record, while examples of from 6 to 7 feet long are not uncommon in Grimsby market. 

 This fish has a wide distribution, occurring on both sides of the North Atlantic and North 

 Pacific, being most abundant in deep water. The halibut which are brought into the markets 

 of Grimsby and Hull are chiefly caught off the coasts of Iceland and the Faroes with 

 long lines. 



The SOLE is a shallow-water fish, feeding chiefly upon worms, crabs, and shrimps. These 

 it apparently hunts by smell, gliding over the sea-bottom, and tapping with the lower side 

 of its head, which is provided with sensitive organs of touch in the shape of filaments. By day 

 it conceals itself by burrowing in the sand, coming out after dark to feed. 



The TURBOT resembles the brill, from which it may be distinguished by the greater breadth 

 of the body in proportion to the length, the absence of scales, and the presence of large bony 

 tubercles scattered over the surface. In Great Britain the turbot is most abundant in the 

 English Channel. 



The BRILL closely resembles the turbot not only in general form, but in the numerical 

 superiority of the females, and in the habits of the young, which, like the turbot, are surface- 

 feeders and possess an air-bladder. 



