PISHES OF THE GULF OF MAINE 509 



are nearly uniform in height from end to end in the witch, and that it lacks the 

 mucus pits so characteristic of the blind side of the head of the latter, are reliable 

 field marks in the separation of these two species. 



The smooth flounder is peculiar among our local flatfish for its sexual dimorph- 

 ism. Besides the difl'erence in the scales of the two sexes noted above, the pectorals 

 on the eyed side are longer (about four-fifths as long as the head) and more pointed 

 in the rough-backed males than in the smooth-backed females. 



Color. — The "smoothback" varies from grayish to dark muddy or slaty brown 

 or almost black above, either uniform or yariously mottled with a darker shade of 

 the same tint, with the dorsal, anal, and caudal fins of the general ground color. In 

 specimens we have examined these fins were mottled, but Storer described them~as 

 black spotted.'^' The blind side is white. 



Fig. 262, — Smooth flounder (Liopsttta ptitnnmi) 



Size. — Tliis is the smallest flounder common in the Gulf of Maine, growing to a 

 maximum length of only about a foot and to a weight of about a pound and a half. 



General range. — The distribution of the smooth flounder in American waters is 

 Arctic-boreal. It is definitely recorded from as far north as Ungava Bay in Hudson 

 Straits, hence no doubt occurs along the Atlantic coast of Labrador, also from the 

 Gulf of St. Lawrence, and there are specimens from St. Anthonys on the eastern 

 coast of northern Newfoundland in the Museum of Comparative Zoology. We 

 find no record of it on the outer coast of Nova Scotia between Cape Breton and Cape 

 Sable, but probably it has been overlooked there, being widespread in the Gulf of 

 Maine, as detailed below. It is known as far south as Providence, R. I. Its range 

 is probably continuous with that of its Polar relative (L. glacialis) of the Arctic 

 coasts of North America and Siberia. Indeed, it is a question whether any valid 

 distinction can be drawn between the two. 



