196 



THE OPAL SEA 



Crabs, 

 lobsters and 

 barnacles. 



The hard 

 Khelt. how 

 funned. 



Equipment 

 for defense 

 and attack. 



forms of sea life and one of the most widely 

 distributed. There are ten thousand living spe- 

 cies in the class, to be found in almost every 

 sea; and they have almost every proportion 

 from the microscopic to the gigantic. All the 

 different varieties of crabs, lobsters, craw fish, 

 shrimps, prawns, barnacles and acorn shells be- 

 long to it. The general name, Crustacea, comes 

 from the hard calcareous casing which every 

 member of the family wears. It is in kind a 

 jointed armor, grown and colored by the outer 

 skin, and cast off or " shed " at periods when 

 the wearer has become too large for it. A new 

 shell is speedily grown in its place, but until 

 it is hardened the crustacean hides in sand or 

 rock or weed. The equipment for defense and 

 attack in this class is something extraordinary. 

 Their bodies are constructed for bending, twist- 

 ing, jumping; they have members for swim- 

 ming, feet for walking, legs for burrowing, 

 claws hooked and toothed for grasping and 

 tearing, and jaws for grinding. In addition they 

 are given antennce for touch, compound eyes 

 for seeing, sense organs for smell and taste, 

 and, finally, respiratory organs for either land 

 or sea. 



With such resources in attack and defense it 

 is not surprising to find a belligerent spirit. 



