PROTOZOA 



33 



-1 



The bud, or buds, are formed in the floor of this cavity. 



When they leave the 



parent they are ciliated ; 



a fact which lends support 



to the vievy that the Acine- 



taria are descended from 



the Oihata. They at first 



lead a wandering Kfe, but 



after a time settle down, 



lose their cilia, and acquire 



tentacles. 



Class V. Sporozoa. 



The members of this 

 class are all parasitic ; and 

 correlated with this condi- 

 tion of life is the absence 

 of locomotor organs, the 

 absence of any mouth, — 

 the nutriment being ab- 

 sorbed all over the body,- — 

 and a reproductive process 

 which results in the forma- 

 tion of a very large number 

 of young. The nucleus is 

 always single even when the 

 ceU is divided into two 

 chambers. No contractile 

 vacuole is present. The 

 cortical layer of protoplasm 

 may show traces of fibrilla- 

 tion. 



Of the four sub-classes 

 which compose this class, 

 that of the Gregarinidea 

 is the most important. The 

 true Gregarines, with very 

 few exceptions, pass their early life as cell parasites, afterwards 



Fig. 26. — Acineta grandis, Sav. Kent. 



1. Stalk. 5. An example of 



2. Knobbed tentacles. Acineta lemnarum, 



3. Membranous shell. stowing relative size 



4. Nucleus. of the two species. 



