﻿CLASSES AND SUB-KINGDOMS. 



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Class Arachnida (spiders). Animals whose bodies are 

 segmented. The segments grouped together into two re- 

 gions, the cepbalo-thorax and the abdomen. Having four 

 pairs of legs, and breathing air through openings in the body. 



The word arachnida is derived from a Greek word, 

 arachne, spider. 



Arachnids- 



Class Crustacea (lobsters, crabs, barnacles, etc.). Difficult 

 to define, but including animals which pass through a series 

 of moults in their growth, though in this respect resembling 



