CLARK: RECENT CRINOID FAUNA 11 



a. Arctic Ocean: Arctic Ocean, and the extreme north Atlantic. 



6. East Asiatic: Western shores of the Seas of Okhotsk and 

 Japan. 



2. Antarctic: Antarctic regions, and the west coast of South 

 and North America to Alaska, westward to the western Aleutian 

 Islands, and southward to southern Japan. 



a. Continental Antarctic: Coasts of the Antarctic continent, 

 Kerguelen, and Heard Island. 



b. Megellanic: Cape Horn northward to Alaska, westward 

 to the western Aleutian Islands, thence southward to Tokyo 

 and Sagami Bays, Japan. 



c. Abyssal: The abysses in the extreme south, and in the east- 

 ern and northern portions of the Pacific and Atlantic Oceans; 

 probably also the abysses in the eastern part of the Indian Ocean. 



The various geographical divisions of the Indo-Pacific-Atlantic 

 fauna occupy each a relatively circumscribed area, supporting 

 distinctive species; but the derived faunas, while characteristic 

 of the area as delimited above, have ill-defined borders and en- 

 croach more or less upon the surrounding faunas. 



Thus the Malayan fauna, especially characteristic of, and 

 apparently originating in, the very warm water of the Malayan 

 littoral, is very widely spread wherever very warm water occurs; 

 a few of its distinctive species reach southwestern Japan, one 

 reaches the Hawaiian Islands, and several reach Australia, where 

 they overlie the species of the Australian fauna proper, especially 

 on the northeastern and eastern coasts, reaching as far south as 

 Perth and Sydney; Ceylon also supports a few representatives 

 of this fauna. The Littoral Atlantic fauna, excepting in the 

 Mediterranean Sea, overlies the true Atlantic fauna. The other 

 derived faunas similarly have extended their ranges more or less 

 into territory occupied originally by other faunal units. 



The derived faunas appear to be the dominant faunas of the 

 present seas, composed of the most vigourous and most adaptable 

 elements in the original Indo-Pacific-Atlantic stock. This 

 latter now appears to be on the road to complete submergence, 

 owing to its inability to adapt itself as a whole to the increasingly 

 diverse oceanographical conditions. 



