THE PLEURONECTID.E, OR FLAT FISH. 311 



form and symmetrical colour which belong, more or less, 

 to nearly all others of this class of animals. The form 

 of the flat fish is so well known to every one, from the 

 frequency of their being served up at our tables, that 

 there is no occasion to enter on a tedious description. 

 The genera, comparatively, are very few ; and when we 

 have seen a plaice and a sole, we have seen the two most 

 dissimilar forms yet discovered in the whole family. 

 On a cursory view, it appears as if the body of these 

 fish was flattened in the same way as that of the skates, 

 but this is only an analogical resemblance ; that of the 

 PkuronectidcB is compressed vertically, while that of 

 the Raidce, or skates, is depressed horizontally : this dis- 

 tinction should always be kept in mind when we are 

 comparing the repesentations of these fishes in other 

 families ; for many of the Chcstodonidce (which are the 

 flat fish of the spine-rayed order of Acanthopteryges) are 

 just as much compressed, and some (as Psettus Cuv.) 

 even more than the PkuronectidcB; but then the position 

 of the eyes, both being placed on one side of the head, 

 renders their distinctions very obvious. It is impossible, 

 in fact, to conceive a more beautiful union of analogical 

 characters than are to be found in this singular-shaped 

 group. Placed as one of the types of the order Mala- 

 copteryges, the PkuronectidcB should bear a relation 

 both to the ChcetodonidcB, or chaetodons, on one side, and 

 to the Raidce, or rays, on the other : this they accord- 

 ingly do, by having the body excessively high and com- 

 pressed, the fins partially covered with scales, and the 

 rays semi-spinous : on the other hand, they show a 

 marked resemblance to the Raidce in having both the 

 eyes placed on one and the same surface of their bodies, 

 and in one of these surfaces being of a different colour 

 from the other. These two characters, throughout the 

 whole class, are solely possessed by the Raidce and the 

 PkuronectidcB ; and these analogies not only corroborate 

 the correctness of the situation we have assigned to each 

 of these groups, but are borne out by the similarity of 

 the habits of the Raidce and the PkuronectidcB, in laying 



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