12 BULLETIN 15, UNITED STATES NATIONAL MUSEUM. 



Atlantic Jind from the seas north of Europe and of western Asia and 

 seem to me to be entitled to the name of a Circumpolar fauna: 



OpMura sarsii. Ophiopholis aculeata. 



Ophiura nodosa. Amphiura sundevalli. 



Ophivra stuwitzii. Ophiacantha bidentata. 



As regards the occurrence of a West Indian element in the North 

 Pacific fauna, the following species have all been taken in the Gulf 

 of Mexico, Caribbean Sea, or subtropical Atlantic: 



Ophiura sculptilis. Ophiacantha bairdi. 



Ophiernus adspersus. Asteronyx loreni. 



Ophiomusium, lymani. 



But it must be noted that all of them are known from the East 

 Indian region and perhaps represent an intertropical fauna. At any 

 rate, with the possible exception of OpJiiacantha hairdi, they can not 

 fairly be considered as distinctively West Indian. The extent of an 

 intertropical fauna is one of the points in the geographical distribution 

 of marine animals upon which much light is needed. That such a 

 fauna exists seems almost certain. 



The ophiuran fauna of the Okhotsk Sea is not extensive, the 

 Albatross collecting only thirteen species there (stations 5014-5030). 

 Of these five are certainly representative of the Bering fauna, 

 while the other eight belong to the widespread Oceanic group. 

 To the north and east around the southern end of Kamchatka and 

 off the Kurile Islands (stations 4794-4805), six additional species 

 were taken, all belonging to the Bering fauna. Passing south and 

 west through La Perouse Strait into the (julf of Tartary, and thence 

 southward along the western coast of the Hokkaido to Tsugaru 

 Strait (stations 4982-501.3), no essential change in the fauna is found; 

 the few ophiurans taken are all of either the Bering or the Oceanic 

 fauna. On the other haml, passing through Yezo Strait along the 

 eastern and southern coasts of the Hokkaido (stations 5031-5045), 

 we meet with one species (OpJiiura penichra) which, although not 

 taken farther south, is at least suggestive of the Honshu fauna. 

 Passing southward from Tsugaru Strait, in the Sea of Japan (stations 

 4807-4841) we meet at once with Opliiura stipJira, a characteristic 

 Honshu species, while Ophiothrix Icoreana, an even more characteristic 

 species, was taken in Hakodate Bay and in Tsugaru Strait. Although 

 Ophiura cediplax was taken above Sado Island, no other representa- 

 tives of the Honshu fauna were taken north of the Noto peninsula, 

 while the Oceanic fauna is still represented by at least three species 

 and the Bering fauna by two or three. As the vicinity of Tsuruga is 

 reached, although Ophiura sarsii is still common, the other Oceanic 

 and the Bering species disappear and are replaced by five Honshu 

 species. Crossing the thirty-sixth parallel and passing into the east- 



