582 



BIOLOGY OF THE PROTOZOA 



generally with the exception of CMlodon uncinatiis described by 

 MacDoiigall (1925). The race of Parameciuin with an increased 

 number of contractile vacuoles described by Hance (1917) may 

 prove to be another example; or changes in organization of Para- 





Fig. 238. — Chilodon uncinatus; third division and interchange of nuclei of diploid 

 (A) and tetraploid (B) stock. (After MacDougall.) 



mccium which were due to heat applied during the "sensitive" 

 period of reorganization after conjugation and which persisted 

 through five successive generations by conjugations, may be still 

 another (Jollos-, 1923). 



