General Observations on Fishes.--Their Locomotive Organs.--Tail. --Fins.--Classification of Fishes by Cuvier.--Air-Bladder.--Scales. --Beauty of the Tropical Fishes.--The Gills.--Terrestrial Voyages of the Anabas and the Hassar.--Examples of Parental Affection.-- Organs of Sense.--Offensive Weapons of Fishes.--The Sea-Wolf.--The Shark.--The Saw-Fish.--The Sword-Fish.--The Torpedo.--The Star-Gazer.--The Angler.--The Chætodon Rostratus.--The Remora, used for catching Turtles.--Defensive Weapons of Fishes.--The Weever. --The Stickleback.--The Sun-Fish.--The Flying-Fish.--The numerous Enemies of the Fishes.--Importance and History of the Herring Fishery.--The Pilchard.--The Sprat.--The Anchovy.--The Cod.--The Sturgeons.--The Salmon.--The Tunny.--The Mackerel Family.--The Eel. --The Murey.--The Conger.--The Sand-Launce.--The Plectognaths.--The Sea-Horse.--The Pipe-Fish.--The Flat-Fishes.--The Rays.--The Fecundity of Fishes 186 CHAPTER XIII. CRUSTACEA. CRABS--LOBSTERS. How are they distinguished from the Insects?--Barnacles and Acorn-shells.--Siphonostomata.--Entomostraca.--King-Crab. --Edriophthalmia.--Sandhoppers.--Thoracostraca.--Compound Eye of the higher Crustaceans.--Respiratory Apparatus of the Decapods.--Digestive Organs.--Chelæ or Pincers.--Distribution of Crabs.--Land Crabs.--The Calling Crab.--Modifications of the Legs in different species.--The Pinna and Pinnotheres. --Hermit Crabs.--The Lobster.--The Cocoa-nut Crab.--The Shrimp. --Moulting Process.--Metamorphoses of Crabs.--Victims and Enemies of the Crustaceans.--Their Fecundity.--Marine Spiders and Insects 243 CHAPTER XIV. MARINE ANNELIDES. The Annelides in general.--The Eunice sanguinea.--Beauty of the Marine Annelides.--The Giant Nemertes.--The Food and Enemies of the Annelides.--The Tubicole Annelides.--The Rotifera.--Their Wonderful Organisation.--The Synchæta Baltica 262 CHAPTER XV. MOLLUSCS.