Reports on the results of dredging, under the supervision of Alexander Agassiz, in the Gulf of Mexico, and in the Caribbean Sea, 1877-79, and along the Atlantic coast of the United States during the summer of 1880, by the United States Coast Survey steamer "Blake," Lieutenant-Commander C. D. Sigsbee, U. S. N., and Commander J. R. Bartlett, U. S. N., Commanding. XVI. Preliminary report on the Comatulae.