100 PROTOZOA. 



Exantples. — LabyriiUhula (on Algce), ChlaniydoDcyxa {on bog-moss). 



5. Heliozoa, with stiff processes radiating from a spherical body. 

 The outer protoplasm has usually larger vacuoles than the internal 

 portion ; there may Ije numerous nuclei, and one or more contractile 

 vacuoles. Skeletal structures may be entirely absent {Actiiiosphceriuin) ; 

 they may be represented by a jelly-like envelope (Heterophiys) ; or by 

 loose flinty needles [Raphidiophiys] ; or, more rarely, by a connected 

 framework { Clathrtdina). Multiplication by division or by spores. 

 Conjugation occurs. Encystation and spore making, and in some young 

 forms flagellate phases are known ; the stiff processes become more 



Fk 



26. — Formation of shell m a simple Foraminifer. 

 (After Dreyek.) 



In A the shell has one chamber ; />', C, and D show the formation 

 of a second. Note outflowing pseudopodia and the enclosure of the 

 shell by a thin layer of protoplasm ; note also the nucleus in the 

 centra! protoplasm. 



amteboid in ibod catching. Compared with Lobosa, the Heliozoa are 

 passive. The majority occur in fresh water. 



Examples. — Ac/iiiosp/nn-itii'i, Actiiwphrys sol (sun animalcules) ; 

 Raphidiophrys, forming colonies ; Clathnilina, stalked. 



6. FORAMINII.-ERA. — Predominantly amceboid forms, with fine 

 branching and interlacing processes issuing from the main mass, which 

 is always within a shell, calcareous in the majority, arenaceous or chiti- 



