SKIN, SCALES, AND SPINES 93 



middle of each side, and generally some smaller ones near the 

 bases of the fins; all these are more or less widely separated 

 from one another, and the rest of the body is naked (Fig. 143D). 

 The Leather Car^D {Lederkarpfen) has a thick, roughened skin, 

 which is entirely devoid of scales. 



In some of the Cat-fishes (6'z7wrozWffl) , Frog-fishes {Antennariidae) , 



Fig. 40. FISHES WITH TUBERCLES. 



A. Diamond Flounder {Platichthys stellatus), X i ; b. Black Sea Turbot {Rhombus 



maeoticus),X\\ C.Japanese Flounder (Kareius btcoloratus),X i ; D. Bat-fish 



(Ogcocephalus vesper tilio), X i- 



and in the Cling-fishes {Gobiesocidae) , the scales are reduced to 

 soft papillae of the dermis. In many of the more speciahsed Flat- 

 fishes (Soles, Tongue Soles, etc.) some of those on the under 

 side of the head become transformed into tiny membranous 

 filaments, which are very sensitive and act as organs of touch. 



Among other instances of specialisation may be mentioned 

 the presence of bony scutes along the middle of each side in the 

 region of the lateral fine. These may result from the modifica- 

 tion of ordinary scales or may develop as entirely new struc- 



