Columbia subject headings:
Harvard subject headings:
Marine ecology--Germany--History--19th century.
Marine ecology--History--19th century.
Oceanography--Germany--History--19th century.
Oceanography--History--19th century.
Seas--Germany--History--19th century.
Seas--History--19th century.
Princeton subject headings:
Marine ecology--Germany--History--19th century.
Marine ecology--History--19th century.
Oceanography--Germany--History--19th century.
Oceanography--History--19th century.
Seas--Germany--History--19th century.
Seas--History--19th century.