PREFACE Crustaceans were collected by several members of the Harriman Expedition, particularly by Professor Trevor Kincaid, Professor W. B. Ritter, and Dr. Wesley R. Coe. After the return of the Expedition these specimens were arranged by groups and sent to specialists for study. The Decapods have been elaborated by Miss Mary J. Rathbun, who has included in her investigation the extensive collections from the Pacific coast already in the United States National Museum, so that her paper may be regarded as a comprehensive revision of the group for the west coast of North America from California to Arctic Alaska. The Isopods have been treated by Miss Harriet Richardson, the Amphipods by Dr. S. J. HoImes, tlie Pycnogonids by Dr. Leon J. CoIe. The chapter headings are from the facile pens of Mrs. Louise M. Keeler and Mr. F. A. Walpole- the Amphipods by Mr. Ialpole, the others by Mrs. Keeler. C. HART MERRIAM, opportunities for studying the Pacific fauna, as the material is in some cases...