Mr. Clark, who worked with the echinoderms collected during the U.S. Bureau of Fisheries survey of Japanese waters by the steamer Albatross in 1900, describes the Ophuirans of the North Pacific Ocean in the collection of the United States National Museum, many of which were undescribed. Much of the new material came from a 1906 collection made by the Albatross, and represented a larger collection in volume.