THE LIFE OF THE SIMPLEST ANIMALS 



17 



fine threads interlace when they touch each other, thus 

 forming a sort of protoplasmic network outside of the shell. 

 In some cases there is a complete layer of protoplasm 

 part of the body protoplasm of the protozoan surround- 



PIG. W.PolystomeUa strigittata, one of the Globigerinte. After MAX SCHULTZB. 



ing the cell externally. The Radiolaria, whose shells are 

 made of silica, possess also a perforated membranous sac 

 called the central capsule, which lies imbedded in the 

 protoplasm, dividing it into two portions, one within and 

 3 



