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. — Xorthern 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 DilTerent 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 X\ I. 



DISPERSION OF FRESH \V.\TER 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 X\7I. 



DISPERSION OF ERESH-W.\TER FISHES. (Co„li„„cd.) 



Barriers to Dispersion of Fresh-water Fishes: Local IJarriers. — Fa\-orable 



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



— The Suletind. — The Cas.siquiare. — Two-Ocean Pass. — Mountain Chains 



— U]>land Fishes. — Lowland Fishes. — Cuban Fishes. — Swampy Water 



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



DisTXTsion still in Operation 



^ 297 



