74 THE STORY OF ANIMAL LIFE 



structures which are seen to lie in front of them 

 are the tentacles or feelers. Z>, Serpula, is com- 

 mon on shells and stones. The animal has a 

 plumy bunch of gill-filaments, brilliantly coloured, 

 and a stopper with which it can close the mouth 

 of its tube. This precaution is necessary to 

 keep out its predatory cousins belonging to the 

 Errantia, who poke in their heads and eat the 

 tube-dwelling worms. E is Spirorbis, a minute 

 form with a coiled tube, which looks at first 

 sight like a small univalve shell. It is common 

 everywhere, on shells and stones, and encrusting 

 Fuci and other seaweeds, which it sometimes 

 covers almost completely. Spirorbis also has 

 plume-like gills and a stopper. In the latter is a 

 cavity where the creature's eggs are incubated 

 for a time. 



The reader will have no difficulty in finding 

 and identifying both Serpula and Spirorbis. Tere- 

 bella is frequently washed up on a sandy shore. 

 On the Lancashire coast one may feel sure of 

 finding this and many other sand-dwelling ani- 

 mals, after an east wind. The east wind, driving 

 back the water at low tide, kills these creatures 

 with cold, and presently they are washed up dead 

 or dying by the high tide. Pectinaria, another 

 worm with a tube of sand-grains, in which, how- 

 ever, the body lies loosely within the tube, may 

 also be found in thousands under the same cir- 

 cumstances. 



We must not forget to say something regard- 

 ing the most commonly known member of the 

 Vermes, the familiar earthworm. The worms are 

 the first of the great group of animal life in which 

 we find true land animals. There are terrestrial 

 forms among the lowest worms, at least forms 



