EQUATORIAL ZONE. 



275 



Indian ocean, with the varying configuration of their coasts, 

 and the difi'erent nature of their bottom, its long peninsulas, 

 and its archipelagoes, and the scattered islands of the tropical 

 Pacific, render this part of the globe the most perfect for the 

 development of fish-life. The fishes of the Indian and Pacific 

 oceans (between the Tropics) are almost identical, and the 

 number of species ranging from the Eed Sea and east coast 

 of Africa to Polynesia, even to its westernmost islands, 

 is very great indeed. However, this Indo-Pacific fauna does 

 not reach the Pacific coast of South America. The wide 

 space devoid of islands, east of the Sandwich Islands and 

 the Marquesas group, together with the current of cold water 

 which sweeps northwards along the South American coast, 

 has proved to be a very effectual barrier to the eastward exten- 

 sion of the Indo-Pacific fauna of coast fishes ; and, conse- 

 quently, we find an assemblage of fishes on the American 

 coast and at the Galapagoes Islands, sufficiently distinct to 

 constitute a distinct zoological division. 



The following list, which contains only the principal 

 genera and groups of coast fishes, will give an idea of the 

 affinity of the tropical Atlantic and Indo-Pacific : — ^ 



