LAMPREYS AND FISHES 



separate. They all live in swift streams, lying on the bottom, 

 hidden among the stones, often supporting themselves by 

 their expanded ventral and anal fins, frequently resting with 

 their heads turned to one side. They make lightning-quick 

 darts and short stops like rabbits. They feed upon the insects 

 of the riffles, especially upon midge larvae. 



Johnny darter, Boleosoma nigrum. — The "Johnny" or 

 tessellated darter is common in both swift and sluggish streams 

 and ponds, in New England and New York. It is about three 

 inches long, pale olive brown with black W-shaped markings 

 on its sides (Fig. 282). Its name "tessellated" refers to the 

 fine black flecking on its tail fin. In spring the males are 

 almost all black. The' Johnny darter often swims about over 

 a mud bottom, an unconventional place for darters. 



Size. — Up to 2 and }4 inches. 



Distribution. — Eastern states, and westward to Pennsyl- 

 vania, Great Lakes, Dakota. 



Fig. 283. — Miller's thumb, Cottus bairdii. 

 Sculpins — CottidcB 



Miller's thumb, mufflejaw, muddler, C?)ttus. — These are 

 grotesque little fishes with heads too large for their bodies 

 and flattened like the proverbial miller's thumb. Fullgrown 

 ones are not usually more than five inches long. Their general 

 color is olive green or brownish, speckled and mottled with 

 darker brown, the whole pattern matching the bottom of the 

 clear streams and ponds where they hide. They are smooth- 

 skinned except for fine prickles behind the front fins and 

 the warty roughness on the head. 



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