... considerable portion of the upper side. The chief difference between the Baltic and the North Sea is the reduced salinity of the former, so that it might be supposed that fresher water caused the greater development of the dermal skeleton. On the other hand, a species or geographical variety of the Plaice, whose proper is P. glacialis, is found on the Arctic coasts of Asia and America, on both sides of the extreme North Pacific, and on the east coast of North America. In this form the bony ... — Hormones and Heredity • J. T. Cunningham
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