Chapter IV C&lenterates 



WHILST fully appreciating the immense 

 potentialities of a single cell of proto- 

 plasm with its powers of multiplication, 

 and its capacities for assuming a vast 

 variety of shapes, the vast diversity of 

 forms assumed by the Ccelenterata, or 

 animals with a " hollow interior," must 

 strike us with amazement. And yet the 

 plan upon which they are all built is 

 intrinsically the same. The body of life 

 comprised under the title Ccelenterata 

 the hydroid polyps, the jelly-fishes, the 

 sea-anemones, and the corals is repre- 

 sented by free-swimming individuals, 

 tree-like growths, and great stony masses 

 big enough to support large houses. But 

 in all cases the animal matter is the same 

 in general form and structure and is 



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