200 THE RIVER-SIDE NATURALIST. 



THE RIVER BULL-HEAD. 



The RIVER BULL- HEAD or MILLER'S THUMB (Cottus gobio, 

 Cottidce) receives, according to Yarrell, its first name from 

 the bigness of its head as compared to the rest of the body, 

 and the second from its likeness to a miller's thumb, which 

 in former days was used in a peculiar manner for the 

 purpose of testing the quality of the meal, whereby the 



THE MILLER'S THUMB. 



thumb became broad, flat, and smooth, and exactly like the 

 shape of the fish's head. Yarrell states that he derived this 

 information from the late John Constable, R.A., " whose 

 father, being one of the large Suffolk millers, was early 

 initiated in all the mysteries of that peculiar business." 



This fish is a very undesirable inhabitant of a trout- 

 stream, for although it occasionally chokes a dabchick by 

 sticking in its gullet, yet it is a great devourer of ova and 

 fry, and is never satisfied. 1 It should be exterminated 

 wherever possible. It generally frequents shallow streams 

 and hides itself under stones, darts quickly on its prey, 

 but is a bad swmimer. 



The bull-head has a variety of provincial names. It is 



1 " DABCHICK AND BULL-HEAD. 



" SIR, I found a dead dabchick in the stream here the other day, 

 choked by a large bull-head, and am having it set up in defunct 

 attitude by Mr. Peachey, of Elizabeth Street, Pimlico, as a monument 

 of feathered vice. I am, &c., 



"C. R. C. H. 



SLOUGH." 



