252 COLE 



In the table the localities are arranged in order from the north 

 and west toward the east and south, from Bering Sea to southern 

 California. The species are similarly arranged in the order of 

 their first occurrence in the list of localities. It will be noticed 

 that there is a great gap in the series of localities extending the 

 whole distance from Prince William Sound, Alaska, to northern 

 California, except for the single record of Stimpson at Puget 

 Sound. This gap is indicated in the table by double lines. 



It seems at first surprising that more of the species are not 

 identical with North Atlantic forms; but when it is taken into 

 account that only four species have been found to the northward 

 on the Pacific side, and that one of these, Phoxichilidium femora- 

 turn Rathke, is circumpolar, being found also on the coasts of 

 northern Europe, the proportion does not appear so small. Fur- 

 thermore, two Bother of the four species, Ammothea latifrons and 

 Ammothea alaskensis, correspond fairly closely to the European 

 forms Ammothea echinata (Hodge) and Ammothea l&vis (Hodge) 

 respectively, and it is not unlikely that they have been differen- 

 tiated from common circumpolar types. 



In discussing the distribution of the Hydroids collected by the 

 Harriman Alaska Expedition, Nutting (: 01) takes exception to 

 the definition of the Pacific faunal areas made by Dall ('76) in 

 'An Introductory Note to the Report on Alaskan Hydroids, by 

 Mr. Clark.' Dall extended what he called the Oregonian Fauna 

 from Monterey to the Shumagin Islands; Nutting would not 

 extend this southern fauna farther northward than about the 

 region of Puget Sound. Then, instead of a break at the Shu- 

 magin Islands with a distinct fauna beyond (called the Aleutian 

 by Dall), the results of further research would seem to show that 

 from Puget Sound to the Aleutian Islands the fauna is fairly con- 

 tinuous and homogeneous, and to this Nutting has applied the 

 name Alaskan Fauna. Reasoning from the close relation existing 

 between Pycnogonida and Hydroid colonies, the former being so 

 often found with and perhaps obtaining their food from the latter, 

 and the larvae, in some cases at least, being known to be parasitic 

 upon the Hydroids, either living within the gastral cavity (Dohrn, 

 '81, p. 76) or attached to the outside with the proboscis buried in 

 the body of the host (von Lendenfeld, '83), it would not be at all 



