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- 



FIG. lO.Polystomella strigillata, one of the Globigerinae. After MAX SCHTTLTZE. 



ing the cell externally. The Kadiolaria, 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 



