220 MALACOP. SUB-BRACH. FLAT FISH. 



central line be drawn, the parts on each side of that 

 line do not correspond to each other, according to 

 the general rule that has been observed in the for- 

 mation of animals. The head appears as if it had 

 been forcibly twisted to one side — sometimes to the 

 right, sometimes to the left — the mouth, by this 

 process, to have become distorted, and the eyes 

 thrown out of the same line, and frequently rendered 

 unequal in size. The body is very much com- 

 pressed, and extremely deep, almost surrounded by 

 the large dorsal and anal fins, while the ventrals 

 seem like a continuation of the latter. The colour 

 is always confined to one side, that on which the 

 eyes are placed, and the other is invariably white. 

 The result of the conformation just noticed is, that 

 these fish swim on their sides, as expressed in the 

 family name, which is derived from -rXguga the side, 

 and yjjxrjjs a swimmer. Like the Rays and Skates, 

 they are intended to inhabit the bottom of the 

 ocean, seeking their food from or near the surface 

 of the submerged land ; they are therefore destitute 

 of a swimming bladder, and it will at once be per- 

 ceived how admirably adapted their form is for their 

 destined residence. 



We occasionally find that the eyes and colour are 

 placed on the side opposite to that they usually 

 occupy in the same species, and individuals exhibit- 

 ing this peculiarity are said to be reversed: at one 

 time they were thought to be distinct species. At 

 other times, again, both sides are coloured alike, in 

 which case the specimen is said to be double* 



