ELERY RONALD BECKER. 



Sphxrita from Amoeba Umax Dug., which they found to be 

 different morphologically in the younger developmental stages 

 from 5. dangeardi. No comparison was made with S. endogena. 

 Dobell (1919) mentions a Sphxrita in the free forms of the 

 parasitic amceba, Endolimax nana. Kessel (1924) found a 

 Sphxrita in Councilmania muris, entozoic in mice and rats. 

 There are a number of other papers on Nucleophaga, closely 

 related to Sphxrita, except that it is found in the nucleus. It 

 was originally described from Amoeba verrucosa by Dangeard 

 (1895), but we will not discuss this genus any further here. 



The greater number of Endamceba citelli from one ground 

 squirrel were parasitized by a species of Sphxrita. This material 

 showed so great an abundance of individuals in different stages 

 of development that it has been possible to follow almost the 

 complete life-cycle of this interesting cytozoic organism. The 

 earlier stages of development of the parasite were the first to 

 be seen within the cytoplasm of the amoeba (Figs. 2, 3, 4). The 

 first impression was that they represented nuclei in the process 

 of construction from chromidia. Further search revealed the 

 large plasmodia with maturing spores (Fig. 7), which led to the 

 correct identification of the bodies as stages of the life-cycle of a 

 Sphxrita. It would not be surprising if intracellular parasites of 

 protozoa have led observers astray more often than is generally 

 known; e.g., Leidy in Plate VII. of his "Fresh-water Rhizopods 

 of North America" figures a number of specimens of Amosba 

 villosa with "large and coarsely granular nuclei," which "nuclei" 

 were probably typical sporangia of a Sphxrita, the "coarse 

 uniform granules" being the spores. This interpretation is 

 strengthened by Fig. 15 of the same plate, which Leidy describes 

 as representing "collapse of the contractile vacuole and the 

 bursting of one of the nuclei with the simultaneous escape of the 

 granules or spores of the nucleus and the contents of the con- 

 tractile vacuole." What he probably observed was the liberation 

 of the spores from a sporangium of Sphxrita. 



The life-cycle of Sphxrita citelli can perhaps best be described 

 by referring frequently to the figures of the plate. Fig. 2 

 represents an amoeba with two parasites in the earlier stages 

 of development. The lower one has a fine cell membrane, 



