CLASSES AND SUB-KINGDOMS. 185 



Class Arachnida (spiders). Animals whose bodies are 

 segmented. The segments grouped together into two regions, 

 the cephalo-thorax and 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. 



Aeachnids- 



Sttb-Kingdom Yeemes (worms). Class Annelida (angle- 

 worms, leeches, certain sea-worms, etc.). Animals whose 

 bodies are made up of an indefinite number of segments, 

 bearing appendages which are not jointed, and in the larger 

 number of groups having bunches of bristles or setce upon 

 the sides of the body which act as supplementary organs of 

 locomotion. The name annelida is derived from the Latin 

 word wanuhis, a ring. 



