MALACOPTERYGII SUB-BRACHIATI. 323 



deep water, and utter a grumbling sound when drawn up to the surface. Two species are known, inhabiting the 

 depths of the Mediterranean and Atlantic. 



THE SECOND FAMILY OF THE MALACOPTERYGII SUB-BRACHTATL 

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



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

 vertebrated 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 eyes 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 little 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 spinous processes ; the dorsal extends along the whole back ; the 

 anal occupies the lower edge of the body, and the ventrals are sometimes united 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 sonic 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, liut very differently 

 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 botli 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. limmula, 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- 

 crocephalut, the Lamindcr, with the eyes smaller, nearer each other, and the back finely mottled with brown and 

 yellow, [lioth these are found in the salt water, as is also /'. leminoidet, the Long, or Rough Dab, which 1ms the 

 body elongated, something like a saw, md it approaches that species and quality. /'. polo, the Craved 1 lake, lias 

 the lie.nl small, the right eye considerably in advance of the left, with the body yellowish-brown, and the tins 

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



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



in the northern seas, and weighs from three to four hundred pounds. Its tlesh is rather coarse and dry, but 



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



the left side, 'when as all the others hitherto notieed have them on the right side, unless when understood to be 

 reversed ;] and one is oblong, with a Straight lateral line, and large BCalt S. 



RAOM&ltf, the Turbot genUS. Teeth as in tin' Halibut, but the dorsal advances in front of the eyes, and the anal 

 COmea to lb" edge of the jaws. The eyes are generally on the left, and in some they are separate.) by a low crest. 



R, maxinut, the Tnrbot, is the most estee d of the family. Its height If nearly equal to Its length, its form a 



truncated rhombus, aud with the lateral Ime i h an le d. The upper or left side is brown, and betel with 



tubercles; but rei med spa Imi as are sometimes taken. R. VUlgorit, Hnll, is rounded on the sides, (Ms the body 

 Without tub.reles.and the fust ravsof the dorsal split into filaments. The eyes aie BSUalTj on the Ml side. It is 



not so much esteemed as Tnrbot, still it is a good Bah, R Mrhu, Topknot : mouth small, almost rertii al ■. teeth 

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

 but aot so conspicuous asfna ther species, which lias the body turned the other way, or the eyes on the 



right side, and the literal line nearly straight. li. SMfSWfewM, the Whiff I body oblong, mouth wide, lateral line 



nearly straight, upper colour brown : it is uot much esteemed. it. wmoglomm, the Scarlet Fish: oblong, ey> | 

 the left, fln-rayi exti nding beyond the membrane, and of a yellowish-brown colour. 



Y 2 



