PROCEKDINQS 



OF THE 



WASHINGTON ACADEMY OF SCIENCES 



Vol. Ill, pp. 157-216. PLS. xiv-xxvi. May ii, 1901 



PAPERS FROM THE HARRIMAN ALASKA 

 EXPEDITION. 



XXI. 



THE HYDROIDS. 



By C. C. Nutting. 

 University of Iowa. 



CONTENTS : 



Introduction 157 



Geographic distribution 158 



Systematic discussion 163 



INTRODUCTION. 



The collection of Hydroida secured by the Harriman Ex- 

 pedition is of exceptional interest, and proves to be one of the 

 most important and most extensive collections of these beautiful 

 forms of marine life thus far made in Alaskan waters. Our pre- 

 vious knowledge of the Hydroid fauna of this region rested almost 

 exclusively on the collection made by Dr. W. H. Dall and his 

 associates during the years 1871-1874 and reported on by Dr. S. 

 F. Clark. ^ The number of species listed in Clark's report is 41, 

 in which was included Co^finia arcta, now known to be merely 

 the gonosome of JLafoea. Of these 40 species, 15 are well known 

 British forms, and only one was then known from the Atlantic 

 coast of the United States. The remaining 24 species were new. 



^ Report on the Hjdroids collected on the coast of Alaska and the Aleutian 

 Islands by W. H. Dall, U. S. Coast Survey, and party, from 1871 to 1874. 

 inclusive. Proc. Acad. Nat. Sciences, Philadelphia, 1876. 



Proc. Wash. Acad. Sci., May, 1901. (i57) 



