Begins. "The following account of the Polychaeta of Puget Sound and neighboring waters is primarily based upon a collection made by Nathan R. Harrington, lately deceased, a member of the Columbia University Zoological Expedition to that region in the summer of 1896. The collection, comprising thirty-four species belonging to seventeen families, was sent to me in January, 1898. Preliminary examination showed that the collection, although meagre, in part poorly preserved, and almost destitute of data, contained much of interest. It seemed best, however, to defer any publication of results until more and better material could be obtained. Thanks to the good efforts of several collectors, notably Prof. William E. Ritter and )Iiss Alice Hobertson, both of the University of California, very substantial additions have been made to the original collection. These, together with two species from Victoria, B. C., kindly contributed by Prof. William A. Herdman, raise the total number of species to fifty-one, distributed in thirty-four genera and twenty-six families (see Table, p. 384)- practically all the Polychaeta known to occur in the Puget Sound region.