102 The Geographical Distribution of Fishes 
parallel series. Yet the fauna of Polynesia is strictly East 
Indian, modified by the omission or alteration of species, and 
that of Australia is Indian at the north, and changes to the 
southward much as that of Africa does. In its marine fishes, 
it does not constitute a distinct ‘“‘realm.” The East Atlantic 
(Europe-African) series follows the same general lines of change 
as that of the West Atlantic. It extends, however, only to the 
South Temperate Zone, developing no Antarctic elements. The 
relative shortness of Africa explains in large degree, as already 
shown, the similarity between the tropical elements in the two 
Old-World series, as the similarity in tropical elements in the 
two American series must be due to a former depression of the 
connecting Isthmus. The practical unity of the Arctic marine 
fauna needs no explanation in view of the present shore lines 
of the Arctic Ocean. 
Minor Faunal Areas.—The minor faunal areas of shore fishes 
may be grouped as follows: 
East Atlantic. East Pacific. West Pacific. 
Icelandic, Arctic, Arctic, 
British, Aleutian, Aleutian, 
Mediterranean, Sitkan, Kurile, 
Guinean, Californian, Hokkaido, 
Cape. San Diegan, Nippon, 
Sinaloan, Chinese, 
West Atlantic. Panamanian, East Indian, 
Greenlandic, Peruvian, Polynesian, 
New England, Revillagigedan, Hawaiian, 
Virginian, Galapagan, Indian, 
Austroriparian, Chilian, Arabian, 
Floridian, Patagonian. Madagascarian, 
Antillzan, Cape, 
Caribbean, North Australian, 
Brazilian, Tasmanian, 
Argentinan, New Zealand, 
Patagonian. Antarctic. 
Equatorial Fishes Most Specialized. —In general, the dif- 
ferent types are most highly specialized in equatorial waters. 
The processes of specific change, through natural selection or 
