THE MILLERS-THUMB AND ITS HABITS 

 By THEODORE GILL 



A quite common and characteristic denizen of the cold streams of 

 the entire northern hemisphere is a small brownish fish with a wide 

 head, which is mostly found recumbent on the bottom of the stream 

 and generally under a stone or some other object used for partial 

 concealment. The name best known is Millers-thumb. It is one of 

 a large family. The species are numerous and constitute a natural 

 group which may advantageously be recognized as a subfamily 

 (Cotfincv) closely related to the marine fishes known along the coast 

 of the United States as Scul]:)ins ( Myoxoccphalince) . Although the 



species are mostly confined to fresh water, 

 a few may occasionally wander into brack- 

 ish or moderately salt water, as the Baltic 

 Sea, the Gulf of St. Lawrence, and the 

 North Pacific Ocean. Very little is known 



i'lG. 27. — Skull of Sculpin. After Girard. 



t - ,X to most persons about these fishes, but 

 considerable has been published in a scat- 

 FiG. 26.— Skull of Sculpin. tered form, and the principal data are for 

 After Girard. t;he first time brought together in the pres- 



ent article ; these have been arranged so as to facilitate comparison 

 with the account of "the Sculpin and its habits," jniblished in the 

 Smithsonian Miscellaneous Collections in 1905 (vol. 47, p. 348-359). 



II 



The Millers-thumbs, or Cottines, are a subfamily of Cottids^ dis- 

 tinguished from the Sculpins or Myoxocephalines by the restricted 



' The characters of the Cottids are given in the article on "the Sculpin" 

 (p. 349). 



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