RIVER BULLHEAD. 57 



species of the genus Cottus, on account of the large size of the 

 head ; as we also use the words Bullfinch, Bullfrog, Bulltrout, 

 and Bullrush, to indicate species of large comparative size. 



As the term Bullhead is thus considered to refer to the 

 large size of the head, so the name of Miller's Thumb given 

 to this species, it has been said, is suggested by, and intended 

 to have reference to, the particular form of the same part. 



The head of the fish, it will be observed by the accompa- 

 nying vignette, is smooth, broad and rounded, and is said to 

 resemble exactly the form of the thumb of a miller, as produced 

 by a peculiar and constant action of the muscles in the exercise 

 of a particular and most important part of his occupation. 



It is well known that all the science and tact of a miller 

 is directed so to regulate the machinery of his mill, that 

 the meal produced shall be of the most valuable description 

 that the operation of grinding will permit when performed 

 under the most advantageous circumstances. His profit or 

 his loss, even his fortune or his ruin, depend upon the exact 

 adjustment of all the various parts of the machinery in opera- 

 tion. The miller's ear is constantly directed to the note 

 made by the running-stone in its circular course over the bed- 

 stone, the exact parallelism of their two surfaces, indicated by 

 a particular sound, being a matter of the first consequence : 

 and his hand is as constantly placed under the meal-spout, to 

 ascertain by actual contact the character and qualities of the 

 meal produced. The thumb by a particular movement spreads 



