NORTH PACIFIC OPHIURANS IN THE COLLECTION 

 OF THE UNITED STATES NATIONAL MUSEUM. 



By Hubert Lyman Clark, 



Of the Museum of Comparative Zoology, Camhridge, Mass. 



INTRODUCTION. 



The collection of Echinoderms made in Japanese waters by the U. S. 

 Bureau of Fisheries steamer Albatross in 1900 was placed in my hands 

 soon after its return to this country, and a preliminary examination 

 showed that the Ophiuroidea formed the largest and perhaps the 

 most interesting section of it. Various circumstances interfered with 

 the completion of a report at that time, so that the collection was 

 still in my hands when, in 1907, I was asked to undertake the study 

 of the much more important and extensive series of ophiurans col- 

 lected by the Albatross in 1906. After that work was well under way, 

 Doctor Rathbun, of the National Museum, requested me to take 

 over the entire series of North Pacific ophiurans in that museum and 

 make my report inclusive of all three collections. It was agreed to 

 make lat. 35° N. the southern limit on the American coast, of 

 the oceanic area to be covered by the report, and lat. 30° N. the 

 southern limit on the Asiatic coast. As a result of this arrangement 

 there has been confided to my care an extraordinary amount of 

 material, consisting of over 40,000 ophiurans, representing about 

 190 species. The great bulk of these were collected by the Fisheries 

 steamer Albatross during her various voyages to and from Alaska, 

 Bering Sea, and Japan, but there is also much material from Alaska 

 collected by a number of different naturalists, some of it more than 

 forty years ago. There are also some very valuable specimens col- 

 lected by the United States exploring expedition in Japan half a 

 century ago. 



In view of the fact that very little work has ever been done on the 

 ophiurans of the North Pacific, it is not strange that a very large per- 

 centage of the species in this collection proves to be undescribed. 

 Since the publication of Lyman's monograph, based on the Cliallenger 

 ophiurans, the number of known species has increased from 450 to 

 over 1,100. Aside from a number of less important papers, Lyman's 

 34916°— Bull. 75—11 1 



