IX, EARTHWORMS, LEECHES, AND SEAWORMS 



Branch VHI. — Annulata (annuhis, ring) 



Annulata. — With very few exceptions tlie members of 

 this branch liave their bodies divided externahy into a 

 number of rings which represent a division of the internal 

 parts into a series of segments. The segmented worms 

 are mdely distributed. They are foimd on land, in fresh 

 water, and in the sea. 



Example of the Branch — the Earthworm 



External features. — The body is long and cylindrical, 

 bluntly pointed at one end and roundetl and flattened at 

 the other. The Ijluntly pointed end of its body which 

 bears the mouth is known as the anterior end. The opposite 

 end of the body is known as the posterior end. At the an- 

 terior end of the body is a small lobe which overhangs 

 the mouth and is called the proMomium, or "lip." A 

 short distance back of the anteri;))' end is a swollen ring, 

 or band, called the clitellum. It is furnished with glands 

 for secreting nracus to form the egg capsules. If a 

 worm be carefully watched, it will he found that a certain 

 side of the body is always held up].ierni()st and away from 

 the ground. This is called the dursal side. The side of 

 the body in contact with the ground is called the renlral 

 side. Moreover, the body is plainly divided into rings, or 

 segments. The segments seem to be marked off by super- 



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