PHYLUM PROTOZOA IN GENERAIv 



69 



majority are marine, and Glohigerina is a typical example. The dis- 

 integrating calcareous shells of this organism constitute a great mass 

 of material on the bottom of the ocean which is known as globigerina 

 ooze and from which chalk is formed, (c) Mycetozoa, are character- 

 ized as being able to produce enormous plasmodia containing hun- 

 dreds of nuclei and contractile vacuoles, as well as having ability to 



Fig. 26. — Shells of different Foraminifera. A, Rhahdamina abyssorum (X4.5) ; 

 B, Nodosaria hispida (X18); C, Globigerina buUoides (X55). (From Borradaile 

 and Potts, The Invertebrata, published by The Macmillan Company, after various 

 authors. ) 



reproduce by spore formation. They live quite commonly in masses 

 of decaying vegetable material upon which they feed, (d) Heliozoa 

 is a group with thin, radially arranged, threadlike, unbranched 

 pseudopodia. Actinophrys sol is a common one found in fresh-water 

 streams and ponds, (e) Badiolaria is a marine group with fine, ray- 



