PROCEEDINGS OF THE UNITED STATES NATIONAL MUSEUM haued l^^fVvi, 0?!^ hy the SMITHSONIAN INSTITUTION U. S. NATIONAL MUSEUM Vol.89 Waihington: 1940 No. 3101 THE POLYCLAD FLATWORMS OF THE ATLANTIC COAST OF THE UNITED STATES AND CANADA By LiBBiE H. Hyman Since the work of Girard and Verrill and the one paper by Wheeler in 1894, the polyclads of the Atlantic coast of North America have not been studied until recently, when the subject was simultaneously and independently attacked by Dr. A. S. Pearse, of Duke University, and myself. Pearse and his associates ^ published their work in three papers appearing in rapid succession which antedated my article on some of the same species (Hyman, 1939a) . More recently I undertook this revision of all the Atlantic coast material contained in the collec-tions of the United States National Museum, including the polyclads studied by Pearse, Littler, and Walker. Dr. Pearse himself furnished me with two shipments of live polyclads. In the hope of discovering whole mounts mentioned by Verrill in his account of New England polyclads (1892-93), I made a trip to the Peabody Museum of Yale University and examined large numbers of Verrill's slides. Nothing of value, however, was discovered. Thanks are expressed to M. D. Burkenroad, assistant curator, for time and trouble expended in helping me with these slides. The work of Pearse and his coworkers was based on whole mounts. These have now been studied in serial section, except in the case of one specimen, of which only the type was available. Unfortunately, Pearse's specimens were found to be in extremely bad histological condition, so that the sections were often unsatisfactory. It has nevertheless been possible to determine the status of practically every species. 1 Pearse, 1938 ; Pearse and Littler, 1938 ; and Pearse and Walker, 1939. 251544 — 40 1 449
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