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Fishes.—Electric Fishes ——Photophores or Luminous Organs.— Photo- 
phores in the Iniomous Fishes.—Photophores of Porichthys.— Globe- 
fishes —Remoras.—Sucking-disks of Clingfishes——Lampreys and Hog- 
fishes. — The Swordfishes. — The Paddle-fishes. — The Sawfishes. — 
Peculiarities of Jaws and Teeth ——The Angler-fishes.— The Unsymmet- 
fical Byes-of Flovinders scan ant Soe eee ceili aa Se 51 
CHAPTER VI. 
COLORS OF FISHES. 
Pigmentation.—Protective Coloration—Protective Markings——Sexual 
Coloration—Nuptial Coloration—Coral-reef Fishes——Recognition 
Marks.—lIntensity of Coloration—Fading of Pigments in Spirits.— 
Variation Patterties.. sie tiintcs ho Aubg saaie enalews eer theact bees sleep nee 79 
CHAPTER VII. 
GEOGRAPHICAL DISTRIBUTION OF FISHES. 
Zoogeography.—General Laws of Distribution.—Species Absent through 
Barriers——Species Absent through Failure to Maintain Foothold.— 
Species Changed through Natural Selection.— Extinction of Species — 
Barriers Checking Movements of Marine Species.—Temperature the 
Central Fact in Distribution—Agency of Ocean Currents.——Centers of 
Distribution —Distribution of Marine Fishes—Pelagic Fishes——Bas- 
salian Fishes.— Littoral Fishes.— Distribution of Littoral Fishes by Coast. 
Lines —Minor Faunal Areas.—Equatorial Fishes most Specialized.— 
Realms of Distribution of Fresh-water Fishes.— Northern Zone.— Equa- 
Loriall Zone —SOuthern -ZOme 5s cdo eon dha 8 sole wea teog eae eben et go 
CHAPTER VIII. 
BARRIERS TO DISPERSION OF RIVER FISHES. 
The Process of Natural Selection.—Local Barriers —Favorable Waters 
Have Most Species—Watersheds.—How Fishes Cross Watersheds.— 
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 sin Operationiay cjoss wit u ky rihanna ies due Aloe Bod 106 
CHAPTER IX. 
FISHES AS FOOD FOR MAN. 
The Flesh of Fishes.—Relative Rank of Food-fishes—Abundance of Food- 
fishes.— Variety of Tropical Fishes.— Economic Fisheries —Angling. .* . 129 
