ANNULATA. 203 



lead independent lives. This is not found in the earth- 

 worm and leeches. But even in these there is great power 

 of reproducing lost tissues that have been cut away. 

 For example, an earthworm may have the first 6 or 8 

 segments, including the mouth and brain, removed and if 

 kept under favorable conditions will gradually re-form all 



FIG. 61. Outline drawing of a leech (Clepsine). 



Questions on the Figure. 1 Which is anterior and which posterior 

 end? Are the external markings true signs of segmentation in 

 leeches? Where are the suckers in this animal? Is this its per- 

 manent shape? How does it move? 



the head organs and be enabled to live its independent 

 life again. The same is true of the posterior region. 

 Both of these powers point to the fact that they are of 

 lowly organization. 



220. Definition of the Annulata. The most important 

 characteristics of the group are : the well- segmented body ; 



