82 



A HISTORY OF FISHES 



fishes [Gobiesocidae) are curious little creatures found between 

 tide-marks among loose stones and shells, to which they adhere 

 firmly by means of their adhesive discs. The disc is relatively 

 large and of a complicated structure ; it is composed largely of 

 pads of thickened skin, but the widely separated pelvic fins 

 and even the much modified bones of the pectoral girdle may 

 contribute to its formation (Fig. 35B). 

 Among the Flat-fishes [Heterosomatd) , the asymmetry so 



Fig- 35- — FISHES WITH VENTRAL SUCKERS. 



A. Lump-sucker (Cyclopterus lumpus), X |^ ; b. Cling -fish (Lepadogaster gouani), 



X\ ', c. Bornean Sucker {Gastromyzon bornunsis)yX^ ; d. Lower surface of 



Black Goby (Gobius niger), X ^. 



characteristic of the group extends to the pelvic fins in a large 

 number of species. In the Scald-fish {Arnoglossus) , for example, 

 the pelvic of the left side, that is to say, of the upper or 

 coloured side, is large and placed along the lower edge of the 

 body like a fringe, whereas that of the lower side is quite 

 small and placed at some distance from the edge. In some 

 specialised Australian Flat-fishes {Rhombosolea) the pelvic fin 

 of the blind side, in this case the left side, has disappeared 

 altogether, and the other elongate fin has become joined to the 



