PROTOZOA IN GENERAL 



277 



where they may remain for weeks. When this mosquito bites a man, 

 some of the saliva with sporozoites flows into the wound, and the 

 process of asexual multiplication begins over again in the red cor- 

 puscles of this person as a new host. 



Colonial Protozoa 



There are some species of Protozoa in which the individual cells 

 exist in groups called colonies. This formation frequently results 

 from incomplete separation of the cells following division. In some 

 of these forms only two cells adhere, but in others the cells may 



Codoposi^a 



fandonna 



Carchejium 



Fig. 92. — Different types of colonial Protozoa. Eudorina, a simple colony ; 

 Pandorina, a colony within a gelatinous capsule ; Ceratium, a linear colony ; 

 Carchesmm, a stalked infusorian colony ; Codonosiga, a stalked flagellate colony. 

 (Drawn by Joanne Moore.) 



remain attached after many divisions, with the result that thou- 

 sands of cells are built into the group. In some species there is a 

 jellylike, spherical envelope inside of which the colony of ceUs 

 remain. In certain species the cells are stalked, and the new cells 

 remain attached to the stalk, giving a branching colony. Pan- 

 dorina and Eudorina are typical examples of the former, while 

 Epistylis and Carchesium are typical examples of the latter. These 

 types of colonies are known as spheroid and arhoroid or dendritic 

 respectively. Colonies like that of Ceratium with individuals ar- 

 ranged in a line form a linear one, and colonies of irregular arrange- 



