Nonc. Begins: This paper embodies the results of some weeks of study of a portion of the annelid collection of the United States National Museum. I am indebted to the authorities of the Museum and to Dr. Waldo L. Schmitt, curator of the division of marine invertebrates, for making this material and the necessary facilities available to me. I am deeply grateful to the American Association of University Women for a financial grant that made it possible for me to undertake an examination of the types of many specimens of marine annelids of the New World in the United States and abroad. The list of specimens reported on at this time comprises 50 species, alphabetically listed below and followed by the name herein accepted and the page where my discussion of it appears.