304 LEISURE-TIME STUDIES. 



bodies respectively; a supposition, the mere mention of 

 which is sufficient to show its absurd and erroneous nature. 

 It may thus be clearly shown that the flat surfaces of the 

 soles and their neighbours, judged by the fact that they 

 bear the paired fins, must represent the sides of their bodies. 

 And an examination of the other series of fins found in these 

 fishes would show the latter statement to be correct. The 

 second set of fins possessed by fishes includes the so-called 

 " unpaired " fins, which are invariably situated in the middle 

 line of the body. With the " back " fins, and " tail fin," as 

 examples of these latter appendages, every one is ac- 

 quainted , and when we look for these fins in the flat-fishes 

 we find them developed in a very typical fashion. There is 

 a long " back " fin, for instance, fringing the body above, 

 and defining the back for us; a second or "anal" fin of 

 equal extent, borders the body below ; and the tail fin is 

 equally well developed. An examination of the tail fin 

 alone would in fact show us the true relationship of the 

 various surfaces of these fishes since in all fishes this fin is 

 set vertically, and not crosswise, as in the whales. Placing 

 the tail fin in its proper position, that is, setting our flat-fish 

 with the back fin uppermost, we then note that the flat sur- 

 faces of the tail will correspond with the flattened surfaces of 

 the fish, and that the latter must therefore be the sides of the 

 animal. 



But there still remain for comment and explanation the 

 remarkably placed eyes, which, according to our observa- 

 tions, are now seen to be situated on one side of the body, 

 and not on the back, as is commonly supposed. The side 

 on which the eyes are placed is usually the left side ; but in 

 several species they are situated on the opposite surface ; 

 the eyed side being, as we have seen, the dark-coloured sur- 

 face. To this latter side, also, the mouth is to a large extent 

 drawn, this aperture thus becoming unsymmetrically deve- 

 loped. Occasionally, also, it may happen that in species of 

 flat-fishes in which the eyes are habitually situated on the 

 left side, these organs may be placed on the right, and vice 



