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