THE SARCODINA 



163 



manner as in man, namely, by assimilative and dissimilative 

 changes within the individual cell. 



Reproduction and Life Cycle. — Up to the present time, amoebas 

 have been rather difficult forms to maintain for long periods in 





B-2. Endogenous budding 



A. Binary Fission in A.proteus 



.B-1. Naegleria gruberi, binary fission 



B-3. 



Exogenous budding 



B-4. Encystment and emergence from cyst 



through pore 



B-5. Flagellate stages C. Flagellulie, Sp. 1 



Fig. 89. — Phases in the Life cycles of amcebas. 



A, A. proteus, a common fresh-water species. B, 1 to 5, Nmgleria gruberi, one of the 

 soil amcebas, various phases not necessarily in sequence as shown. C, flagellulse of an 

 unknown species apparently in conjugation. (A, after Botsford; B, after C. W. Wilson.) 



laboratory cultures. It is probable that the cells are very minute 

 during part of the cycle and hence difficult to follow with certainty 

 by the methods of pedigreed cultures now used in the study of 

 protozoa. In the large active phase of Amoeba proteus, it is well 



