xii Contents 



Checking Movements of Marine Species. Temperature the Central Fact 

 in Distribution. Agency of Ocean Currents. Centers of Distribution. 

 Distribution of Marine Fishes. Pelagic Fishes. Bassalian Fishes. Lit- 

 toral Fishes. Distribution of Littoral Fishes by Coast Lines. Minor 

 Faunal Areas. Equatorial Fishes most Specialized. Realms of Distribu- 

 tion of Fresh-water Fishes. Northern Zone. Equatorial Zone. Southern 

 Zone. Origin of the New Zealand Fauna 237 



CHAPTER XV. 



ISTHMUS BARRIERS SEPARATING FISH FAUNAS. 



The Isthmus of Suez. The Fish Fauna of Japan. Fresh-water Faunas of 

 Japan. Faunal Areas of Marine Fishes of Japan. Resemblance of Japan- 

 ese and Mediterranean Fish Faunas. Significance of Resemblances. 

 Differences between Japanese and Mediterranean Fish Faunas. Source of 

 Faunal Resemblances. Effects of Direction of Shore Lines. Numbers of 

 Genera in Different Faunas. Significance of Rare Forms. Distribution of 

 Shore-fishes. Extension of Indian Fauna. The Isthmus of Suez as a Bar- 

 rier to Distribution. Geological Evidences of Submergence of Isthmus of 

 Suez. The Cape of Good Hope as a Barrier to Fishes. Relations of Japan 

 to the Mediterranean Explained by Present Conditions. The Isthmus of 

 Panama as a Barrier to Distribution. Unlikeness of Species on the Shores 

 of the Isthmus of Panama. Views of Dr. Giinther on the Isthmus of 

 Panama. Catalogue of Fishes of Panama. Conclusions of Evermann & 

 Jenkins. Conclusions of Dr. Hill. Final Hypothesis as to Panama 255 



CHAPTER XVI. 



DISPERSION OF FRESH-WATER FISHES. 



The Dispersion of Fishes. The Problem of Oatka Creek. Generalizations as 

 to Dispersion. Questions Raised by Agassiz. Conclusions of Cope. 

 Questions Raised by Cope. Views of Giinther. Fresh-water Fishes of 

 North America. Characters of Species. Meaning of Species. Special 

 Creation Impossible. Origin of American Species of Fishes 282 



CHAPTER XVII. 



DISPERSION OF FRESH-WATER FISHES. (Continued.) 



Barriers to Dispersion of Fresh-water Fishes: Local Barriers. Favorable 

 Waters Have Most Species. Water-sheds. How Fishes Cross Water-sheds. 

 The Suletind. The Cassiquiare. Two-Ocean Pass. Mountain Chains. 

 Upland Fishes. Lowland Fishes. Cuban Fishes. Swampy Water- 

 sheds. The Great Basin of Utah. Arctic Species in Lakes. Causes of 

 Dispersion still in Operation 297 



