MALACOPTERYGII SUB-BRACHIATI. 323 



deep water, and utter a grumbling' sound when drawn up to the surface. Two species are known, inhabifin;- the 

 depths of the Mediterranean and Atlantic. 



THE SECOND FAMILY OF THE MALACOPTERYGII SUB-BRACHIAT . 

 Pleuronectid^ (the Flat-fish, or Flounder Family). 



These are all included in the great genus Pleuronectes, which have a character quite unique among 

 vertehrated animals: this consists in the want of symmetry in the head. [An animal is said to be sym- 

 metrical when it is supposed to be divided in a mesial plane, or plane exactly along the middle, in a 

 vertical direction, — the two sides being the exact counterparts of each other, and differing in nothing 

 but in the one being turned to the right, and the other to the left.] These fishes have both ej'es on 

 one si le, and this side always remains uppermost when the animal is swimming, [while all other fishes 

 swim on the belly.] The upper side is in general deeply coloured, while the other side is whitish. The 

 body, from the head backwards, though formed nearly as usual, partakes a httle of this peculiarity. 

 The two sides of the mouth are not equal, and the pectoral fins are rarely so ; the body is depressed, 

 and elevated in the direction of the spmous processes ; the dorsal extends along the whole back ; the 

 anal occupies the lower edge of the body, and the ventrals are sometimes imited with it. [The fins 

 are thus lateral fins, in respect of the swimming of the fish when in motion ; and the action of the 

 spine is vertical, in respect of that position, and not lateral, as in other fishes.] They have six gill- 

 rays ; the abdominal cavity is small, but extends in a cavity imbedded in the flesh on the two sides of 

 the tail, for the purpose of containing some of the viscera ; they have no air-bladder, and they seldom 

 rise far from the bottom. Notwithstanding the peculiarity of the cranium, by that twist of the neck 

 which brings both eyes to one side, the bones are the same as in other families, but very diflferently 

 proportioned. They are found along the shores of almost all countries ; and are, generally speaking, 

 wholesome and agreeable eating. 



Some individuals have the eyes placed in the opposite side to that in which they are generally found 

 in their species, and these are said to be reversed. Others have both sides coloured alike, in which 

 case they are called " Doubles." It is usually the coloured side which is doubled, though occasionally 

 it is the white one. They are subdivided as follows 



P. platessa. Plaice, have a row of sharp teeth in each jaw, and very often pavement-teeth in the pharynx ; the 

 dorsal does not advance more forwards than the upper eye, and both it and the anal terminate and leave smooth 

 spaces before the base of the caudal ; they generally have two or three small coeca, and six gill-rays. P. vulgaris. 

 Common Plaice, has six or seven tubercles, forming a line between the eyes, and spots of Aurora red over the 

 brown on the upper side of the body. The height is but a third of the length ; and the flesh is soft, and soon de- 

 composes. P.Jlesus, the Flounder, similar, but with the spots lighter; some tubercles on the head, and some on 

 the base of the dorsal and anal fins ; and have rough scales on the lateral line. They ascend a considerable way 

 up rivers, and reversed individuals are not unfrequently caught. P. limanda, the Dab, has the eyes large, the 

 lateral line curved above the pectoral, the scales rough, and the upper side brown, with whitish spots. P. mi- 

 crocephalus, the Laminder, with the eyes smaller, nearer each other, and the back finely mottled with brown and 

 yellow. [Both these are found in the salt water, as is also P. leminoides, the Long, or Rough Dab, which has the 

 body elongated, something like a saw, and it approaches that species and quality. jP. pola, the Grayed Fluke, has 

 the head small, the right eye considerably in advance of the left, with the body yellowish-brown, and the fins 

 darker. [All these, and some other species, are found on the British shores, chiefly on muddy or sandy bottoms.] 



Hippoglosus, the Halibut. Shape and fins like a Flounder, lateral line arched, attains the length of six or seven 

 feet in the northern seas, and weighs from three to four hundred pounds. Its flesh is rather coarse and Ary, but 

 it admits of being salted. There are several small species in the Mediterranean, some of which have the eyes on 

 the left side, [whereas all the others hitherto noticed have them on the right side, unless when understood to be 

 reversed ;] and one is oblong, with a straight lateral line, and large scales. 



Rhombus, the Turbot genus. Teeth as in the Halibut, but the dorsal advances in front of the eyes, and the anal 

 comes to the edge of the jaws. The eyes are generally on the left, and in some they are separated by a low crest. 

 R. maximus, the Turbot, is the most esteemed of the family. Its height is nearly equal to its length, its form a 

 truncated rhombus, and with the lateral line much arched. The upper or left side is brown, and beset with 

 tubercles ; but reversed specimens are sometimes taken. R. vulgaris. Brill, is rounded on the sides, has the body 

 without tubercles, and the first rays of the dorsal split into filaments. The eyes are usually on the left side. It is 

 not so much esteemed as Turbot, still it is a good fish. R. AfWiw, Topknot : mouth small, almost vertical ; teeth 

 distinct and sharp ; colour reddish-brown, mottled with black, with a large spot on the lateral line near the tail. 

 but not so conspicuous as in one other species, which has the body turned the other way, or the eyes on the 

 right side, and the lateral line nearly straight. R. mcgastoma, the Whiflf: body oblong, mouth wide, lateral lint- 

 nearly straight, upper colour brown : it is not much esteemed. R. arnoglossum, the Scarlet Fish : oblong, eyes to 

 the left, fin-rays extending beyond the membrane, and of a yellowish-brown colour. 



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