THREADWORMS, HAIRWORMS, BRISTLEWORMS 



Tubifex. — These are slender, red or brownish worms about 

 an inch and a half long, living in tubes with their tails sticking 

 up above the surface of the surrounding mud (Fig. 114). 

 They often form reddish patches on the mud, which in close 

 view look like waving fringes due to the constant motion of 

 the tails. Tubifex depends on abundant decaying organic 

 matter, needing only a moderate amount of oxygen. 



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