OF THE BRITISH ISLANDS. 97 



them, and Blennies, Gobies, and other fishes of at least half 

 their own size, being the common food of the marine 

 species. A single freshwater variety, the little Miller's 

 Thumb, or River Bullhead (Coitus gobio). No. 19, is 

 distributed throughout the clear streams and rivers of 

 Great Britain, but where it rarely attains a greater length 

 than three or four inches. In addition to the preserved 

 specimens in the Day Collection, living examples of 

 this species will be found in the large window aquarium in 

 the Buckland Museum. The marine varieties include the 

 so-called Father-lasher, Sea-Scorpion, or common Sea-Bull- 

 head (Cottus scorpius], No. 20, a beautifully mottled variety, 

 which while on our shores, not known to exceed fifteen 

 inches in length, is reported to attain to four or five times 

 these dimensions upon the coast of Greenland. This 

 variety has been described by Couch under the title of 

 Cottus grcenlandicus. The spawn of the Sea-Bullhead, 

 which consists of a closely united mass of small yellow 

 eggs, having much the appearance of boiled sago, are often 

 met with under stones within tide-marks, and have 

 frequently, within the writer's experience, been deposited 

 by the fish in the tanks of aquaria. The long-spined Bull- 

 head or "Lucky Proach " (Cottus bubalis), No. 21, closely 

 resembles the preceding species, but has longer head 

 spines and frequents deeper water, while the Four-horned 

 Bullhead (Cottus quadricornis\ No. 22, is a rare form, 

 seldom entering British waters, and confined almost ex- 

 clusively to the Artie regions. 



The second division of the Cottida, represented by the 

 Gurnards, genus Trigla, are exclusively salt-water fish, 

 distributed extensively throughout the Temperate and 

 Tropical seas. As many as six species are included in 

 the British list, all of which are esteemed for food. A very 



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