88 THE EVOLUTION OF CONTINUITY 



lateral branches formed as hollow tubes directly communi- 

 cating with each other, and the branches arising from the 

 stem in a spiral at regular intervals as in phanaerogams. 

 If we could soften and at the same time compress the main- 

 stem so as to produce a short wide cylinder in place of the 

 long series of narrow cylinders, or wax " zooids " composing 

 its length, and if we could simultaneously apply the same 

 process to the branches, we would produce results some- 

 what like those drawn in the figure below (Fig. 24). That 



Fig. 24. — Diagram illustrating the probable derivation of the 

 Sea-anemone's structural plan, a, hollow tubular con- 

 tinuously zooidal system of main-stem and branches, b, the 

 result obtained by steady, even, serial and lateral compres- 

 sion in the experiment already mentioned, c, a vertical 

 section showing how the compressed branches would com- 

 municate basally with the central cylinder. The top, or cap 

 of the central cylinder would require to be removed to form 

 the mouth. 



is, we would have a central short cylinder with a ring of 

 others springing from the region of its base, and directly 

 communicating with it in this region. And if even, lateral, 

 compression were exercised during the process the ring of 

 short cylinders would form a closely fitting circular series 

 around the central tube, and give us a wax model of the 

 fundamental plan of the Sea-anemone. 



The central cylinder would represent the oesophagus, 

 whose walls would end abruptly where there was communi- 

 cation with the lateral cylinders ; that is, below the 

 oesophagus there would be a wide cavity bounded by 



