THE TUEBOT. 67 



SUB ORDER IT. PLEURONECTOIDEI. 



FAMILY VIL PLEUROXECTID.E. 



The fishes of this family are popularly termed flat fish. The body is always compressed and 

 flat, the side which rests upon the sea-bed is usually white, but sometimes marked with spots, 

 while the upper side is coloured usually some dull brownish tint, which more or less mimics 

 the colour of the sea-bed on which these fishes live. The eyes, which in the embryo were 

 originally on opposite sides of the head, come both to be placed on the upper or coloured side 

 by the migration of one eye across the head during the development of the animal, so that the 

 bones of the head are remarkably unsymmetrical. Almost without exception the dorsal and 

 anal fins extend the whole length of the body, which is always broad and moderately thick. 

 There is never any air-bladder in these fishes, which are carnivorous and naturally marine, 

 though some of them ascend rivers. Dr. Gunther describes thirty -four genera. The abdominal 

 region of the body is remarkably small, but the roe usually extends backward between the muscles 

 towards the tail. The vent is placed well forward, being often near the throat, and frequently 

 between the ventral fins. In the skeleton the processes of the vertebra? in these fishes are remark- 

 ably long, but are not often much developed laterally. In swimming, all these fishes retain the 

 horizontal position. The chief British members of the family are the Holibut, Dab, Turbot, Brill, 

 the Carter, the Topknot, Plaice, Flounder, and Sole. 



THE HOLIBUT.* 



This is the largest of the flat-fish family. It is rare for a specimen more than five feet long 

 to reach the London market, but one caught near the Isle of Man, and sent to Edinburgh, weighed 

 three hundred and twenty pounds, and measured seven feet six inches long by three feet six inches 

 broad, but they ranga to a far larger size on the shores of Iceland, Greenland, and the banks of 

 Newfoundland, and specimens have occasionally been captured which have reached a length of 

 twenty feet. On the coasts of Norway the fishery is carried on in spring when the nights are 

 clear, so that the fish can be seen on the bottom. Couch states that in some localities the fishermen 

 endeavour to transfix them with a spear, but from the powerful struggles of the fish there is always 

 some danger of the boat being overturned. When pierced it is brought to the surface very slowly, 

 and if possible killed with blows from a club. The species is gregarious, and occurs in the greatest 

 numbers on the Newfoundland coast. It feeds on the smaller flat fish, and many kinds of crabs. 

 The roe is of a pale red colour, and the eggs are deposited in spring. The body is elongated, the 

 mouth wide, and the eyes are on the right side. The teeth in the upper jaw are in a double series, 

 but are wanting in the palatine and vomerine bones. The scales are very small. The lateral line is 

 curved, and the hinder rays of the dorsal and anal fins are double. 



A second species, found in the Greenland seas, has the lateral line straight. 



The Rough Dab, or Sand-sucker, belongs to a nearly allied genus, and is name. I Hippoglossoidea 

 limandoides. It has the lateral line straight, and the small scales have ciliated margins. The conical 

 teeth are in a single series. The species extends along the English Channel and the shores of the north 

 of Europe. It is a broader fish than the Holibut, with a less powerful tail ; it is rare off Britain. 

 The largest specimens seen have a length of fifteen inches. One example caught on the Cornish 

 coast had the stomach filled with the shells of Turritella terebra, the greater number of which contained 

 small hermit-crabs. The upper pectoi-al fin has ten or eleven rays which are never branched. The 

 colour of the upper surface is yellowish -brown, sometimes varied with spots. 



A second species occurs on the Atlantic coasts of the United States. 



THE TURBOT.t 



The Turbot is a broad fish, one and three-fifths as long as wide ; it has no scales properly so 

 called, but scattered over the surface are numerous flattened conical tubercles en the upper side. 

 The lower eye is a little in front of the upper eye, the lateral line makes a semicircular curve above 

 the pectoral fin. The longest rays of the dorsal fin are behind its middle, the colour varies from greyish 

 to brownish, and the surface is sometimes covered with dark spots. Ths Turbot is the most valued of 



* Hippoglossus vulyaris. t Rhombus maximus. 



