FISHES OF THE GULF OF MAINE 501 



171. Winter flounder (Pseudopleuronectes americanus Walbaum) 



Flounder; Sole; Flatfish; Rough flounder; Massachusetts flounder; 

 Mud dab; Blackback; Black flounder 



Jordan and Evermann, 1896-1900, p. 2647. 



Description. — This is a small-mouthed, right-handed species (eyes on the 

 right side and guts on the right) , easily separable from the dab, which is similarly 

 characterized, by the fact that its lateral line is nearly straight (at most only slightly 

 bowed abreast the pectoral fin), the dorsal profile of its head less concave, its nose 

 blunter, its eyes farther apart, its fin rays less numerous, and its fins less tapering 

 in outline. The most obvious difference between the winter and the smooth 

 flounders (p. 508) is that the former is rough scaled between the eyes, the latter 

 smooth, and that the winter flounder has more fin rays. On the other hand it has 



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Fig. 256.— Winter flounder ( Pseudopleuronectes americanus) 



only about two-thirds as many dorsal rays as the witch (p. 511), lacks the mucus 

 pits characteristic of the left (lower) side of the head of the latter, and has a much 

 larger tail, proportionately. It is oval in outline, about two and one-fourth times 

 as long as wide, thick-bodied, and with proportionately broader caudal peduncle 

 and tail than any of our other small flatfish except its newly discovered relative, 

 P. dignabilis (p. 507). The dorsal fin (61 to 69 rays) originates opposite the forward 

 edge of the eye, and is of nearly equal height throughout its length. The anal 

 (46 to 51 rays) is highest about midway and is preceded by a short, sharp spine. 

 The ventral fins are alike on the two sides of the body, and both are separated from 

 the anal by a considerable gap. The mouth is small, not gaping back to the eye, 

 and the lips are thick and fleshy like those of the dab. The left (under) half of 

 each jaw is armed with one series of close-set incisorlike teeth, but the right (upper) 

 side has only a few teeth, or may even be toothless. The scales are rough on the 

 eyed side, including the space between the eyes, but perfectly smooth to the touch on 

 the blind (white) side. 



