74 



PROTOZOA 



two in number, i.e. the nucleus divides into two, one of wliicl 



/ 



2.NucIearia 



3.Clahhrulina 



Fig. 20. — Various forms of Heliozoa. In 3, a is the entire animal and h the flagellula ; 

 c.vac, contractile vacuole ; g, gelatinous investment ; nu, nucleus ; psd, pseudopodia ; 

 sk, siliceous skeleton ; sp, spicules. (From Parker and Haswell, after other authors.) 



goes to the surface as the lirst polar body, and the sister of this 

 again divides to form a second polar body (which also passes to 



