PHYLUM PROTOZOA 



41 



Order 4. Foraminif era. — Rhizopoda, mostly marine, with fine, 

 branching pseudopodia which fuse forming a protoplasmic net- 

 work. Examples: Allogromia (Fig. 20), Globigerina, Discorbina. 



Allogromia (Fig. 20) lives in 

 fresh water and has a chitinous 

 shell (sh.). The shells of many 

 Foraminifera consist of numer- 

 ous chambers connected by open- 

 ings (foramina), and are com- 

 posed of calcium carbonate. 

 When these shells sink to the sea- 

 bottom, they become Globigerina 

 ooze, which solidifies, forming 

 gray chalk (Fig. 21). 



Fig. 20. — Allogromia (order For- 

 aminifera). a, aperture of shell; 

 sh, shell. (From the Cambridge 

 Natural History.) 



Fig. 21. — Foraminifera. Shells 

 as they exist in gray chalk. (From 

 Scott, after a photograph by the 

 Geological Survey of Iowa.) 



2. Class II. Masttgophora 

 a. Euglena viridis 



Euglena viridis (Fig. 22) is a small greenish Protozoon which 

 will serve to point out the characteristics of the Mastigophora. 

 It lives in small bodies of fresh water, and may appear in ameba- 

 cultures (p. 28). 



