336 PECULIARITIES OF PLAICE FROM DIFFERENT FISHING GROUNDS. 



There arc two other specimens fi-om Alaska in the British Museum, 

 collected by the Albatross in the Nushagak Eiver, and obtained from 

 the U.S. Fish Commission. These also I have examined, and have 

 recorded their characters below, lioth are females, and immature ; the 

 smaller is ciliated on the fins, head, and central region of the upper 

 side, but not on the interspinous regions ; on the lower side it is also 

 ciliated in the central region. The larger is ciliated all over the upper 

 side, except the region covered by the pectoral, but not on the lower 

 side. 



Lilljeborg's specimens came from the mouth of the river Dwina, at 

 Archangel, from which place Smitt also obtained specimens. Smitt 

 considers Lilljeborg's species identical with Pallas' cicatricosus, but 

 thinks that there are important differences between this and glacialis. 

 He says that Pallas based his distinction on the deeper form of the 

 body, and greater closeness of the scales in glacialis. The difference 

 reappears, though modified by age and sex, between the specimens 

 brought by Nordenskiuld from the north coast of Siberia, east of the 

 Kara Sea, and the specimens brouglit from the White Sea. The 

 specimens of the east coast of the United States, according to Smitt, 

 also belong to cicatricosus. The narrower form, with fewer or smaller 

 scales, therefore, according to Smitt, occurs in the White Sea, on the 

 east coast of America, and in the Behring Sea ; while the broader form 

 extends along the Arctic shores of America and of Siberia ; the 

 glacialis is a purely Arctic form, while cicatricosus lives in a milder 

 climate. 



The evidence I have been able to examine does not enable me 

 to test Smitt's conclusions with regard to the breadth of body or 

 length of head very completely. I can only point out that the three 

 specimens from tlie coast of Alaska, one of which at 18'3 cm. was 

 mature, agree fairly closely with the proportions given by Smitt for 

 cicatricosus, and at the same time are not markedly narrower or longer 

 in the head than many of the female plaice from the northern part 

 of the North Sea. The male glacialis examined by Smitt were longer 

 than the cicatricosus, all females, which he examined, and may have 

 been older, which would to some extent account for their greater 

 breadth and shorter heads. Smitt does not discuss the spinulation 

 of the scales, and does not even mention that this is on the east coast 

 of xVmerica a sexual character. In the two specimens from the north 

 coast of North America which I have examined, as far as can be judged 

 from their unsatisfactory condition, the spinulation is not greater than 

 in male plaice from the North Sea, but their sex is unknown. The 

 three specimens from the coast of Alaska are all females, and more 

 spinulated than most of the male plaice from beyond the Dogger Bank. 



