Living Lights that Never Die 



283 



though some giants measuring more than an inch in 

 diameter are to be found in the warmer waters, most 

 forms are so small as to be practically invisible. A 

 wonderful work is performed by these shells in building 

 the crust of the earth. They are constantly settling to 



globigerina; a protozoan, the shell of this minute animal is in the 

 center, and from it radiates stiff spines of lime. enclosing the 

 shell is a frothy mass of living substance from which extends 

 numerous fine threads. 



the floor of the ocean. The dead shells are almost the 

 sole constituent of the material that forms the bottom 

 in many regions of the deep sea. They also compose 

 the platforms of coral reefs. The famous chalk cliffs 

 of England are made up of their countless billions 

 which long ago were dropped upon the floor of the 



