6 General Morphology of the Protozoa 



secreted layers (pellicle, theca, lorica, test, and shell of particular groups), 

 and by internal structures such as radiolarian skeletons. The gross mor- 

 phology of protozoan aggregates and colonies depends upon the means 

 by which the individual organisms are bound together. 



COLONIAL ORGANIZATION 



The usual colony consists of similar organisms joined together in 

 some particular jDattern so that the form of the mature colony is char- 

 acteristic of the genus or species. As a rule, any member of the colony 

 may undergo fission or budding. In the Phytomonadida, this is true in 

 Gonium, Pandorina, and Platydorina but apparently not in Eudorina, 

 Pleodorina, and Volvox. However, flagellates isolated from colonies of 



Fig. 1. 3. Arboroid colonies. A. Phalansterium digitatum, branching ma- 

 trix; x290 (after Lemmermann). B. Zoothamnium adamsi, portion of colony 

 showing stalk with continuous branching fibril; diagrammatic (after Stokes). 

 C. Hyalobryon ramosum, loricate type; x720 (after Awerinzew). D. Poterio- 

 dendron petiolatum; each lorica with stalk; x290 (after Lemmermann). 

 E. Cladomonas fruticulosa with continuous branching "lorica"; x290 (after 

 Lemmermann). 



