ANTHOZOA. 71 



Full-grown corals are not always huge masses ; they may be of 

 great delicacy and beauty, as is shown by Fig. 18, which represents 

 Tridacophyllia manicina, and by the three succeeding figures, which 

 represent various deep-sea corals. Case 8b. The discovery of life at 

 great depths — depths as great as the heights of some of the highest 

 mountains of the world — was one of the most interesting discoveries 

 of the second half of the last century, and has led to a great increase 

 in our knowledge of the globe we inhabit. 



