Races of Paramecium. 



529 



Fig. 21. Form and size of races k and i (both aurelia) under conditions of high 

 nutrition. The two had lived together in the same culture for one month; twenty- 

 four hours before the figure was made some bread was added to the culture. Edin- 

 ger drawing apparatus. X 375. 



the cilia at the time of death, as well as to the discharge of the 

 trichocysts. Some individuals however show it, and this was true 



