PHYSIOLOGICAL ACTIVITIES OF THE PROTOZOA 93 



forms like arcella, difflugia, or euglypha, where the cell is enclosed in 

 a test or shell. Here the protoplasm wells out of the mouth opening 

 of the shell until it forms a counterpart of the parent organism, then 

 the nucleus divides, as stated, and the two individuals separate. Such 

 a method is complicated, and to a certain extent anticipated, by the 

 organism, for long before the cell divides the shell plates of a euglypha 

 are formed and stored up in the protoplasm about the nucleus of the 

 parent organism, to be used only when the bud has reached a certain 

 size. They then flow into the bud with the protoplasmic streaming, 

 and arrange themselves on the outside of the bud protoplasm, where 

 they form a tightly fitting shell (Fig. 5, see A, p. 23). In other 

 cases the buds are much smaller than the cell which forms them, and 



Fig. 31 



Dileptus, sp., with distributed nucleus in process of division. Each of tlie chromatin 

 granules is drawn out in the form of a rod and divides (see Fig. 2, p. 19). 



they first appear as mere protuberances on the surface of the parent 

 (Fig. 32, E). This is the case in forms like spherastrum, for example, 

 and several buds may form at one time. These are frequently dif- 

 ferent from the parent and are often provided with motile organs of a 

 difl'erent type. Thus, in the heliozoa the buds may have pseudopodia 

 of the lobose type and move around like small ameba>, or they may 

 have flagella and move around like flagellates. The former are 

 ciilled pseudop(Kli()sj)ores by I^ang, and the latter flagellispores. In 

 all cases, however, the bud soon loses its larval motile organs and 

 develops into an organism similar to the parent (see Fig. 11, p. 31). 

 In the case of acantliocystis, the buds require five davs for their com- 

 plete develoj)inent, the characteristic centralkorn and the ray-like 

 pseudopodia aj)pearing on the sixth day (Schaudinnj. 



