612 • CORAL. 



Coral is thii.s the product of an animal association. It is not the 

 only one; other inferior creatures belonging to the class of polyps 

 sustain and protect themselves liy means of calcareous rods or envel- 

 opes produced in the same' wa}". This is, however, one of the most 

 characteristic and best known. Its history, save some variations of 

 slight importance, applies to an entire group, and its principal interest 

 depends upon the contrast between the weakness of the polyps and the 

 great size of the polyp community. There, as everywhere, union is 

 strength. The isolated individual counts for but little, but association 

 and nuitual aid produce great results. Man often might searcli in 

 nature, even among the most minute beings, for rules for his conduct. 



