Reports on the results of dredging, under the supervision of Alexander Agassiz, on the east coast of the United States, during the summer of 1880, by the U. S. Coast Survey steamer "Blake," Commander J. R. Bartlett, U. S. N., Commanding. XXI. Report on the Anthozoa, and on some additional species dredged by the "Blake" in 1877-1879, and by the U. S. Fish Commission steamer "Fish Hawk" in 1880-82.