THE HYDROIDA 



PACIFIC COAST OF NORTH AMERICA, 



WITH ESPECIAL REFERENCE TO THE SPECIES IN THE 

 COLLECTION OF THE UNIVERSITY OF CALIFORNIA. 



The scope of this paper has broadened since its preparation 

 was begun. It was intended at first to embody the species of 

 hydroids collected off the southern coast of California during the 

 summer of 1901 by the University of California. To obtain a 

 proper view of these species, however, especially from the stand- 

 point of their distribution, not only was it found necessary to 

 consider all the known species of the western coast of North 

 America, but all the previous collections of the University were 

 overhauled and a number of new species brought to light. As a 

 consequence, 140 western species have been distinguished. Of 

 these, 10^ are represented in the University of California collec- 

 tions, 55 (39%) are restricted to this region, and "JO (14"") 

 are new. 



While the lack of collections from the deeper waters along 

 our shore would make any attempt to monograph the West Coast 

 Hydroida premature on my part even were it not unnecessary 

 in view of the enormous task of monographing the Hydroida of 

 North America which is now engaging the energies of Professor 

 C. C. Nutting, I have thought that a key to the known species 

 would be at least a convenience at this time, the more so because 

 there are not likely to be any considerable additions in the near 

 future to the list of littoral species, which are the most accessible 

 and for that reason form the great majority of the total number. 

 In the body of the paper all the species iu the University of 

 California collection are treated, with the exception of those 



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