CLASSES OF PROTOZOA 



133 



the surface at varying depths ; and some are abyssal. They are 

 abundant as fossils,' and of much importance in the formation of the 



ooze of great depths. • , ^ „ 



Examples.— Thalassicola, EucyrUdtum, and the colonial Collozoum 



and Sphcerozoum. ,1 , v 



C. Predominantly active forms (ciliate and flagellate), 



Fig. 61.— a pelagic Foraminifer — Hastigerina {Globigerina) 

 murrayi. — After Brady. 



Note central shell, projecting calcareous spines with a protoplasmic 

 axis ; also fine curved pseudopodia and vacuolated protoplasm. 



generally called Infusorians.— Protozoa, with a definite rind and 

 with 1-3 undulating flagella, aie included as (8) Flagellata, a very 

 large group, among which are such familiar forms as the common 

 Euglena of ponds ; the Monads ; Volvox, a colonial form ; Codosiga, a 

 colony in which the individual cells are furnished with a collar (Choano- 

 flagellata). The Ha^moflagellata are important blood parasites, gener- 

 ally called Trvpanosomes (see p. i47)- 



Modified flagellate forms are included in the groups Dmoflagellata 



