PROTOZOA 



2 9 



of a sphere elaborately pierced with holes and attached to a 

 stalk (Fig. 9). 



1 



Fig. 9. Clathrulina elegans, a stalked Heliozoon. (After Greeff, from 



Calkins' Protozoa.) 



Order 3. Radiolaria 



The Radiolaria (Lat. radare, to radiate) are all marine organ- 

 isms, which greatly resemble the Heliozoa, especially in the 

 arrangement of the pseudopodia. They differ from the Helio- 

 zoa and the Foraminifera, however, in that the protoplasm is 

 divided into two portions, an inner and an outer, by means of a 



