66 A Guide to the Zoological Collections 



The Flat-fishes have the body compressed like a leaf, 

 and lie habitually on one side — either the right or the 

 left — both eyes being placed on one side of the body, 

 namely on the side opposite to that on which the indivi- 

 dual lies. Except in a few deep-sea species the side 

 upon which they rest is colourless ; and in all but a few 

 pelagic forms the side upon which the eyes are situated 

 is coloured, the colouration being, for protective pur- 

 poses, very similar to that of the sand or mud or shingle 

 on which the fish rests. 



In the very youngest stages of their existence Flat- 

 fishes are bilaterally symmetrical, and swim in a verti- 

 cal position, like other fishes ; but as soon as they 

 begin to rest upon one side, which happens very early 

 in life while the tissues are plastic, the eye and orbit 

 of that side become twisted round towards the light, 

 until both eyes come to be on the upper side of the 

 body. 



Flat-fishes occur in all seas : they always live on the 

 bottom, preferably on a sandy bottom. A good many 

 species live in estuaries, and a few live exclusively in 

 fresh water. Sixty-four different species are found in 

 Indian waters, but none of them reach any great size. 



The Flat-fishes of Indian seas are very good to eat, 

 but they are very seldom brought to market. 



The Indian species belong to the following generic 

 groups : — 



(1) Shallow-water genera: — Psettodes, Amoglossus, 

 PseudorhonibuSy Rhomboidiclithys, Psettyllis, Citharicht/iys, 

 Scwiaris, Brachypleura y Solea (including Achirus\ 

 Synaptura, Plagusia, Cynoglossits. 



(2) Deep-water genera : — Chascanopsetta, Lccops, Boo- 

 psetta, Aphorislia. 



Aphoristia, of which four species have been found at 



