THE PROTOZOA 



free (Fig. 22). The presence of a firm shell or coating complicates 

 the process, especially if the shell is a secretion (Fig. 23). In many 



./ 



Fig. 24. Microgromia sociahs Hert., a gregaloid colony. [HERTWIG.] 



cases the new shell-parts are secreted before the act of division be- 

 gins, and when the protoplasm buds out of the original shell-mouth, 

 they are carried with it, and the bud is covered with the newly formed 



A 



K iA*LMA/4 l X^ / v 



.-'" *V*V -^ & "'."' "ft/*?:-: A .'' -kM 



^ftl^^ 



^^^^:%^\^. 



''.o^-jZ&r 





C) OY 0. 



' o . 



*' t> ^-> 



'^* : fc* : " 'fe * S 'C- t: '!, * O ( 



Fig. 25. Uroglena americana Calkins, a sphaeroid colony. 



pieces, which are glued together by means of a chitinous or silicious 

 secretion. 



