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University of California Publications in Zoology [Vol. 20 



glycogen, and massed or scattered, somewhat pointed chromatin bodies. 

 The latter may not be present. 



The advanced cysts in the fresh stool examined by light from a 

 Mazda lamp with blue glass screen have a grayish tone corresponding 

 to the pale olive, light mineral, or pallid neutral gray of Ridgway's 

 "Color Standards and Color Nomenclature." The thick hyaline wall 

 of the cyst stands off the bacteria and in optical section its innermost 



Pig. B 



Fig. G 



Fig. B. Free amoeba of Councilmania lafleuri, with food vacuoles containing 

 bacteria and red blood corpuscles. Ectoplasm sharply separated from the endo- 

 plasm. Nucleus with excentric karyosomes and thin zone of peripheral chromatin. 

 X 1600. 



Fig. C. Budding cyst of Councilmania lafleuri with six nuclei remaining in 

 the cyst and a seventh in a budding amoebula with chromophile cytoplasm. 

 Nuclei with somewhat excentric karyosomes of the dispersed type and some 

 granular peripheral chromatin forming on the nuclear membrane. X 1600. 



zone has a dark brownish tinge. The nuclei are indistinct or faintly 

 outlined. The cliromatoidal bodies, when present, are somewhat more 

 highly refractive than the cytoplasm. 



The cytoplasm in the iodine-easin stain shows more clearly a 

 coarsely irregular alveolar structure, the chromatoidal bodies are more 

 distinct, the nuclei and karyosomes become more evident, and the 

 whole cyst assumes in time a modified chrome yellow tone. Occasion- 

 ally remnants of food vacuoles and their contents are found in pre- 

 cystic stages, and rarely in later encysted phases. 



