326 MARKETABLE BRITISH MARINE FISHES 



other hand, live in deeper, water, and their eggs are of the 

 transparent buoyant kind. 



The four-horned cottus belongs more particularly to the 

 Arctic Ocean and the northern part of the Baltic. It is said to 

 have been taken on the north coast of England and at \Yey- 

 mouth, but neither this nor the fresh water form need be further 

 considered here. 



The Bullheads (Cottus scorpius and C. bubalis}. 



The long-spined form is smaller than the other, not exceeding 

 12 inches in length, and as usually seen only 6 to 9 inches. It 

 is found in the arctic regions and in America, but seems to 

 extend further south than the short-spined form. It is the only 

 species I have found at Plymouth, and is much the commoner 

 species on the west coast of Ireland, while at St. Andrews the 

 short-spined form is commoner. The largest specimen of the 

 sea-scorpion or short-spined form obtained in Britain was 

 1 5 inches long, but the same species is said to reach 6 feet in 

 Greenland. 



In colour the bullheads are brownish or yellow, with large 

 irregular markings of black and white. Occasionally on the 

 south coast, brilliant red or carmine coloured specimens of the 

 long-spined species are taken. These come always from rather 

 deep water, and I think they live among red sea-weed. The 

 carmine-coloured pigment is present in the ordinary dull and 

 dark-coloured specimens found on the shore, but in these it is 

 much obscured by the large amount of brown or black pigment 

 present. In the carmine specimens, the black is reduced and the 

 carmine colour comes into view. The carmine colour extends all 

 over the back and sides, except where it is relieved by patches 

 of pure chalk-white and black : there are also small yellow 

 marks chiefly on the fins, so that these fish present a very 

 striking and gaudy appearance. It seems possible that the 

 variety is not permanent, but due to the influence of coloured 

 surroundings, that is of the action of coloured light, on the 

 changeable pigment-cells of individuals. 



The eggs are deposited in the earlier months of the year, 

 February to April or later. The egg-masses in the smaller form 





