it is therefore easy to guess who is the builder. In 

 the learned language of science it is known as a 

 tubicolous polychaete annelid; but I am content to 

 term it just a worm — for that is what it is, a tube- 

 builder which bears bristles on its body. 



The immediate cause of the miniature mael- 

 strom now becomes apparent. A pair of vermiform 

 feelers, each invested with an iridescent halo o£ 

 brilliant blue, begins to deploy diffidently from 

 the opening. This halo, or peculiar bright blur, is 

 a ciliary effect; the minute hairs with which the 

 feelers are covered vibrate so rapidly that the eye 

 cannot follow their movements. And it is by their 

 movements that the food-bearing currents in the 

 water are produced. By this same process the ani- 

 mal also breathes: the currents that carry sus- 

 tenance, bring fresh supplies of oxygen; so in a 

 sense, it may be said that our worm fetches in its 

 prey at a breath. The currents can also be reversed. 

 Occasionally a particle of debris comes from with- 

 in the tube and is carried outward, close along one 

 of the feelers, seemingly transported over the tips 

 of the moving invisible cilia. Like the worm I have 

 just previously observed, this one appears unwill- 



[138] 



