2 o MARINE AND FRESHWATER FISHES 



remarkable structural feature in the Gurnards is connected, 

 with the peculiar modification of the pectoral fins, certain, 

 usually three, of the rays of which are detached from the 

 others, separately movable, and so constituted that they 

 form ambulatory organs, wherewith these fish are in the 

 habit of literally walking along the bottom of the 

 sea. This assertion may be easily verified by a brief 

 observation of their habits in the tanks of an aquarium. 

 The remaining pectoral rays, united by membrane and 



Fig. 4. — STREAKED GURNARD {Trigla lineata). 



forming the true fin, are also very largely developed, and in 

 an allied exotic genus, Dactyloptents, to such an abnormal 

 extent, that the fish is enabled with their aid to take 

 long leaps above the surface of the water, and is comprised 

 within the category of so called Flying- Fishes. In many of 

 the British Gurnards, the upper surface of the large 

 pectoral fin is beautifully and brilliantly coloured, and 

 notably in the so-called Sapphirine Gurnard {Trigla 

 hirundd), No. 25, in which this region is ornamented with 

 a central ocellus, and surrounding markings of various shades 



