THE STORY OF ANIMAL LIFE 



many varieties, each taking up some different 

 task for the community. Some may be " nutri- 

 tive persons," i.e. commonplace Zooids that have 

 mouths and eat food; some "protective persons," 

 reduced to mere folds 

 orsheathingprocesses 

 to guard the others; 

 some are " stinging 

 persons " armed with 

 enormous quantities 

 of thread cells. Then 

 the whole colony may 

 be like the jelly-fish, 

 a floating affair, and 

 not fixed at all. 



We have several 

 times above referred 

 to the animals known 

 as corallines. It may 

 almost be assumed 

 that the ordinary 

 reader knows what 

 these are ; if not, a 

 little search among 

 the treasures of the 

 sea-shore will almost 

 FIG. 9 . -An example of the Hy- certainly reveal some 



drozoa. A, branch of a Coral- of them, living or 

 line, Sertularia Ellisii, magni- j-.j T L._ t^vHir^ 

 fied. B, the same, more highly dead. 1 he texture 

 magnified. and appearance of the 



dead stems remind one 



of soft horn or dried gelatine; the branching ar- 

 rangement of the stems and the little cells dis- 

 posed at the ends of the branches will easily be 

 shown under slight magnification. Most people 

 will remember the rage for dyed corallines, by 



