Cleve's map of the North Altantic phytoplankton in summer. "Okändt" signifies unknown.
From Cleve, P. T. 1897. A Treatise of the Phytoplankton of the Atlantic and its Tributaries and the Periodic Changes of the Plankton of Skagerak. Upsala Nya Tidnings Aktiebolags Tryckeri, Uppsala, Sweden, 27 pp.