ASTEROIDEA OF NORTH PACIFIC AND AQJACENT WATERS FISHER. 3 



4. To describe the variations of the diflferent forms represented as thoroughly 

 as the material would permit. In many instances large series of specimens em- 

 phasized in a very striking manner the wide and remarkable variations which 

 characterize most species of Asteroidea: 



5. To describe the young stages of the different forms: 



6. To consider the aflinitics of the Asteroidea of the North Pacific to the 

 Asteroidea of other regions; under each species the geographical distribution is 

 given, and, whenever possible, its ])robable relationships are considered in detail: 



7. To present keys to all the families of Asteroidea, and to all the genera of 

 every family represented in the region imder consideration. Care has been ex- 

 ercised to eradicate the numerous errors of current keys, but it is too much to hope 

 that mistakes do not still persist. A considerable jiortion of the time spent in 

 completing this report has been consumed in verifying structural details in genera 

 not directly considered; but, as genera have greatly multiplied in the last ten years, 

 it is boHeved that these keys will prove useful to students of ^Vsteroidea. 



In these days it is impossible to comi)lete a piece of systematic work without 

 the aid of others, and it becomes a pleasant duty to acknowledge this cooperation, 

 always cheerfully rendered. 



Dr. Kichard Rathbun, Assistant Secretary of the Smithsonian Institution, in 

 charge of the U. S. National Museum, has allowed the freest use of all material in 

 the museum under his charge, and forwarded the extensive collection uj)on which 

 this report is primarily based. As previously stated. Doctor Rathbun at one time 

 contemplated preparing a report on this collection. Throughout the progress of 

 the work Doctor Rathbun has rendered every possible aid. In 1907 I worked for 

 a few months at Washington and Cambridge under a grant from the National 

 Museum. 



I am under obligations to Dr. II. L. Clark, Mr. Samuel Ilenshaw, and Prof. 

 A. E. Verrill for the privilege of examining collections in their charge. Doctor 

 Clark subsequently sent several .specimens for examination, and Professor Verrill 

 examined for me specimens of Solaster and forwarded photographs of several of 

 his new species. 



The U. S. Bureau of Fisheries has allowed the use of its collections made 

 during three cruises of the Albatross under the direction of Doctors Jordan and 

 Evermann (1903), Doctors Jordan and Gilbert (1904), and Doctor Gilbert (1906). 



To Dr. Theodore Gill, Dr. D. S. Jordan, Dr. L. Stejneger, Mr. H. C. Oberholser, 

 and Mr. Austin Ilobart Clark I am indebteil for advice and aid in untangling 

 nomenclatural knots. Mr. Clark has not only lookeil up literature inaccessible to 

 me, but also both he and Miss ilary J. Rathbun have greatly aided me by reading 

 a set of proofs. 



Perhaps not least important has been the encouragement I have received from 

 Doctor Jordan and Doctor Gilbert, for the course of the systematist lies rather 

 more frequently through briar tangles and over rough places than where the way 

 is open and fair. 



The drawings and negatives of the photographic illustrations were made by 

 the wTiter. The prints of the latter were made by Mr. T. W. SmiHie, of the U. S. 

 National Museum. 



