154 EDIBLE EISHES OE NEW SOUTH WALES. 



Group II.— ANACANTHINI PLEUEONECTOIDEI. 



Sides o£ the head asymmetrical. 



Family II .— PLEURONECTIDJE. 



Branchiostegals six to eight : pseudobranchia? well developed. Gills four. 

 Body strongly compressed and flattened, with one of the sides, which is 

 always turned upwards, colored, while the other is colorless, or at the most 

 vspotted. Both eyes (except in the very young) situated on the upper surface : 

 sometimes they are rudimentary. The bones of the two sides of the head, 

 though present, are not equally developed or symmetrical. The jaws and 

 dentition may be nearly equally developed on both sides, or more so on the 

 blind side. Dorsal and anal fins very long, undivided : pectorals present, 

 rudimentary, or absent : caudal fi*ee, or confluent with the dor.-^al and anal 

 fins. Scales present or absent. Lateral line on the colored side single, 

 double, or triple. jVo airbladder. 



Geograpliical distribution. — A.11 temperate and tropical seas. 



The " Flatfishes," as the tnembers of this family are generally termed on 

 account of their greatly compressed bodies, undergo remarkable changes 

 during the earlier stages of their existence ; when born they swim on edge, 

 with the dorsal fin above and the anal below, in the same way as do most 

 other fishes, and have then an eye on each side of the head. Tn a short 

 time, however, one of the eyes makes its way round to the other side, which 

 then becomes the upper, and subsequently the colored side, but how this 

 transmigration is effected, whether by passing beneath the integument or by 

 forcing its way through the intervening cartilage, is not yet clearly known. 



Almost all the Pleuronectidse are littoral fishes, very few species being 

 found at any considerable depth ; they are inhabitants of sandy shores or 

 sandy and muddy estuaries, and though as a rule strictly marine, many species 

 penetrate rivers far beyond the influence of the tide, while some have per- 

 manently established themselves in fresh water, and others have been 

 acclimatized therein through human agency. 



Like the preceding this family contains many species of great importance 

 to mankind. 



. Genus I.— PSEUDOEHOMBUS. 



Pseudorhombus.^ Bleeker, Compt. Eend. Ac. Sc. Amsterd. 1862, xiii. Pleuro- 



nect. p. 5. 

 Ternto rhomb us, Macleay, Catal. Austr. Fish. ii. p. 12G, 1881. 



Branchiostegals seven : pseudobranchias present. Cleft of mouth wide. 

 Gill-membranes united beneath the throat, but not attached to the isthmus. 

 Eyes on the left side, without a free orbital edge : interorbital space not 

 concave. Jaws and dentition nearly equally developed on both sides : teeth 

 in both jaws of unequal sizes, and in a single row : vomer, palate, and tongue 

 edentulous. The dorsal fin commences on the snout, its rays and those of 

 the anal are simple. Scales of moderate size or rather small, extending on 

 to the dorsal and anal fins. Lateral line with a strong curve anteriorly. 



Geographical diatribution. — Coasts of Australia, through Malaysia, to the 

 seas of China and Japan, eastward through the Indian seas to the east 

 coast of Africa, and westward to the Pacific coasts of Central and South 

 America. 



