STUDIES IN ANIMAL LIFE. 



131 



colony lias one nutritive fluid 

 ia common. They are all 

 actively engaged in securing 

 food, and tlie labors of eacli 

 enricli all. It is animal so- 

 cialism of the purest kind — 

 there are no rich and no poor, 

 neither are there any, idlers. 

 Formerly the coral - branch 

 was regarded as one animal 

 — an individual; and a tree 

 was and is commonly regard- 

 ed as one plant — an individ- 

 ual. But no zoologist now 

 is unaware of the fact that 

 each polype on the branch is 

 a distinct individual, in spite 

 of its connections with the 

 rest; and philosophic bota- 

 nists are agreed that the tree is a colony of individ- 

 ual plants— not one plant. 



Let us pass from the coral to the stem of some 

 other polype, say a Campanularia. Above is the 

 representation of such a stem, of the natural size, 

 and beside it a tiny twig much magnified. You 

 observe the ordinary polype issuing from one of the 

 capsules, and expanding its coronal of tentacles in 

 the water. The food it secures will pass along the 

 digestive tract to each of the other capsules. Un- 

 der the microscope you may watch this oscillation 



Fig. 20.— Campanulaeia (mag- 

 nified and natural size). 



