94 



PHYSIOLOGICAL ACTIVITIES OF THE PROTOZOA 



Budding, in cases like the last, is very similar to spore formation, 

 and can scarcely be distinguished from it. Many instances of budding- 

 are presented by different groups of the protozoa, and in all of them the 

 process is characterized by the fact that the parent organism continues 

 to live as an individual after giving rise to these motile offspring. In 

 spore formation, on the other hand, the substance of the parent in the 

 majority of cases is used in the formation of the offspring, and it loses 

 its life as an individual. 



In noctiluca the buds are formed after the nuclei divide, and appear 

 as minute swellings on the surface. The nuclei in these swellings 

 divide repeatedly until about five hundred buds are formed; these 



FIG. 32 



mm A 



& f :i ** ^^W^^^lj 



*;.T* -^ 



Entameba histolytica. (After Craig.) .4, organism showing rods and granules of chro- 

 matin in the nucleus, vacuole with some stained substance, and dense ectoplasm; B, the 

 chromatin of the nucleus passing into the cell plasm, where it is distributed as chromidia, shown 

 n C; D, aggregation of chromidia to form secondary nuclei (see Fig. 51, of Ameba limax); E, 

 "spore formation" by budding; F , spores of Entameba histolytica as seen in feces. 



develop two flagella similar to those of the dinoflagellata, and swim 

 off. After a time one of the flagella turns into a tentacle, and the 

 . characteristic structures of the adult are then formed (Ishikawa). 



Budding is the characteristic method of reproduction of the suctoria, 

 and is interesting from the fact that it may be either on the surface, as 

 in ephelota, or inside the body, as in acineta (Fig. 33). The latter 

 condition is derived from the former by the bud-forming area sinking 

 below the surface and being covered over by a membrane so that a 

 small brood pouch is created within which the buds swim about by 

 means of their embryonic cilia before making their escape (Fig. 34). 



