Hitherto our knowledge of Japanese Polychaeta has been limited to collections made in the littoral zone at several points along the southeastern coast between Yokohama and Nagasaki and ably described in three papers by v. Marenzeller, a few species from the Japan Sea described by Grube and McIntosh, and to the results of about half a dozen dredge and trawl hauls made by the "Challenger" at points off Japan, which have been recorded by McIntosh.
At the close of an extended cruise in the South Pacific Ocean, the United States Fish Commission steamer "Albatross" spent the month of May and part of June, 1900, in dredging and trawling along the continental slope of Japan. During this cruise the vessel was in command of Captain J.F. Moser, U.S.N., with Dr. H.F. Moore as naturalist, to whom, and to Dr. H.M. Smith, of the Fish Commission, I owe the pleasure of studying the rich and interesting collection of Polychaeta taken.
During May a line of about seventy dredging stations was run along the coast of Nippon or Hanshu from Yokohama westward about 200 miles, through Sagami and Suruga Bays and the Totomi Sea. These stations were mostly along the steep slope on the inner border of the Black Current, and about or within the 100-fathom line, though the trawl was sometimes sent down to much greater depths. In early June, ten additional stations were established along the coast of northern Nippon, beginning at the lower end of Sendai Bay and extending for about 120 miles northward, entirely within the 100-fathom line. Later in June several dredgings were made in the shallow waters and muddy bottoms off Kamchatka, and others north of the Aleutian Islands in the southern portion of Bering Sea. The details of location, depth, character of bottom, etc., will be found in a list of dredging records of the "Albatross" compiled by Mr. C.H. Townsend, and pubhshed in the Report of the U.S. Fish Commission for 1900. In this paper it has been thought necessary to give only the depth and general locality, together with a list of the station numbers at which each species was taken.
All of the species contained in the collection have been determined and, with the exception of the families Sabellidae and Serpulidae and several species of other families which have been reserved for further study and comparison with material not now available, are recorded in the following list. A large number of species, either new or hitherto unreported from that region, are added to the Japanese fauna. One of the surprises of this study has been the very small number of Marenzeller's species which were taken by the "Albatross." Of the species previously known most of them belong to the circumboreal fauna, several were dredged by the "Challenger" at points off Japan, and the others have been recorded from various more or less distant parts of the world. As Marenzeller has in preparation an account of the geographical relations of the Japanese Polychaeta, nothing more need be said on this subject. The general results remind one of those attained by Verrill along the Gulf Stream slope of North America.