NORTH PACIFIC OPHIURANS IN NATIONAL MUSEUM CLARK. 11 



It is probable that this trio is not an example of a special fauna, 

 but belongs properly with the following group of species, which range 

 from Alaska southward along the American coast and do not occur 

 in the western Pacific: 



Ophiura lutkeni. Amphiodia ocddentalis. 



Ophiura hadra. Amphiodia periercta. 



Amphiodia iirtica. Am,phipholis pugetana. 



One variety {kennerlyi) of OphiopJiolis aculeata is also restricted to 

 this region. Since some of these species occur as far south as Southern 

 California, the group is characteristic of the continental coast and 

 may very appropriately be called the American fauna. 



We find, then, as a result of our study of the geographical distribu- 

 tion of the 189 species of Ophiurans in the collection that we can 

 recognize four quite distinct faunas in the North Pacific, as follows: 



Bering fauna. Extends from the Arctic Ocean southward to Kadiakon the American 

 coast and on the Asiatic side to Tsugaru Strait and even into the Sea of Japan : 35 

 species. 



Honshu fauna. Surrounds Honshu Island, Japan, but especially characterizes 

 the southeastern and southern coasts and extends an unknown distance south- 

 ward: 114 species. 



American fauna. Extends from the Alaskan peninsula southward to California: 9 

 species. 



Oceanic fauna. Found distributed more or less regularly throughout the North 

 Pacific: 18 species. 



(Of the remaining thirteen species, a few are southern species or 

 seem to connect two of these faunal regions, but the distribution of 

 the majority is too imperfectly known to enable us to place them 

 properl}'.) 



Before leaving the matter of geographical distribution there are 

 a few points to wdiich it may be well to call attention — the existence 

 of a circumpolar fauna, the occurrence of West Indian species in the 

 North Pacific, and the position of the line between the Bering and 

 Honshu faunas. 



The existence of a truly circumpolar fauna has been questioned by 

 some zoologists, but I see no reason to doubt that certain species of 

 ophiurans are completely circumpolar in their distribution. At any 

 rate they are known from north of Europe, Asia, and America, and 

 while there are many regions, often of wide extent, where they have 

 not been taken, such negative evidence is of little value, since such 

 areas have, as a rule, never been zoologically explored. Furthermore, 

 there are, of course, many places where local conditions forbid the exist- 

 ence of ophiurans; their absence from such places can not therefore 

 be rightly construed as denying their existence in the region. The 

 following North Pacific species are also known from the North 



