148 
LIFE AND PIER CHILDREN 
Very few people, as a rule, are acquainted with 
the seaworms in their homes, but every one who has 
handled oysters or scallops must have noticed the 
curious round tubes often firmly clinging to their 
shells. These tubes were once the home of a sea- 
worm which has built them of chalk and slime. The 
worm itself is quite loose within the tube and stretches 
Fig- 53- 
A Group of fixed Sea-Worms. 
S, Serpula. /, Tentacle ; f, breathing-plume. 
Sp, Spirorbis. 
T, Tcrebella. 
its body out, scrambling up the sides by the help of 
its bristles and of a number of little comb-like plates 
which grow upon its rings. If you can get a shell 
covered with these tubes from the sea at low tide and 
put it in salt water, you will see a beautiful sight. 
After a time a small scarlet stopper (/, Fig. 53) will 
creep up and out of the tube, and as it rises on a 
