CHAPTER XIII 

 THE RINGED WORMS OR ANNELIDS 



The term worm is one of wide and somewhat indefi- 

 nite significance. The old group called "Vermes," 

 which is Latin for worms, constitutes what Professor 

 Haeckel has called the great lumber room of Zoology, for 

 it includes animals of the most diverse kinds, with little 

 in common except that they do not belong to other groups. 

 Nowadays zoologists parcel the Vermes out into a number 

 of different phyla. One of the largest of these phyla 

 is the Annelida. These are worms having the body di- 

 vided into more or less similar annuli or segments, and 

 provided generally with a body cavity or space between 

 the digestive tube and the body wall. 



There are a great many marine species, some of which 

 are free, active, carnivorous creatures; others are seden- 

 tary, living in tubes and generally subsisting on small 

 organisms. There are many annelids which inhabit fresh 

 water or burrow in the soil. The latter are commonly 

 known as earthworms or angle worms. There are a great 

 many species of earthworms in various parts of the globe, 

 one of the most common and widely distributed being 

 Lumbricus terrestris which is frequently found in gardens 

 and fields both in Europe and in North America. In this 

 species, which we may take as a type, the body is composed 

 of a remarkably uniform series of segments. Just over 

 the mouth there is an incomplete segment called the pros- 

 tomium. At about the anterior third of the body a few 

 of the segments of the mature worm are somewhat thick- 



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