ioo PROTOZOA. 



Examples. Labyrintkula (on Algae), Chlamydomyxa (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 be numerous nuclei, and one or more contractile 

 vacuoles. Skeletal structures may be entirely absent (Actinosph&rium) ; 

 they may be represented by a jelly-like envelope (Heterophrys] ; or by 

 loose flinty needles (Raphidiophrys] ; or, more rarely, by a connected 

 framework (Clathrulina). 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 



FIG. 26. Formation of shell in a simple Foraminifer. 

 (After DREYER.) 



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 

 central protoplasm. 



amoeboid in food catching. Compared with Lobosa, the Heliozoa are 

 passive. The majority occur in fresh water. 



. Examples. Actinosphceriuin, Actinophrys sol (sun animalcules) ; 

 Raphidiophrys, forming colonies ; Clathrulina^ stalked. 



6. FORAMINIFERA. Predominantly amoeboid 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- 



