ENDAMCEBA CITELLI SP. NOV. 449 



which encloses a centrally located, deeply-staining nucleus. The 

 nucleus shows no nuclear membrane or other differentiation, and 

 its diameter is about two thirds that of the cell. The nucleus of 

 the upper specimen has just divided with no apparent spindle or 

 attraction spheres. At this stage the opposing surfaces of the 

 two nuclei are flattened, with the remaining surface of each 

 nucleus convex. The uninucleate and binucleate stages of the 

 cell are about the same size, measuring from 1.9 to 2.5 micra. 



A second bipartate division provides the plasmodium with four 

 nuclei with the planes of both divisions still plainly marked 

 (Figs. 3, 4, 1 8). The organism has become more oval in shape 

 and has increased in size to about 2.5 micra in width and from 

 2.8 to 3.3 micra in width. From this stage the divisions of the 

 nuclei are not necessarily simultaneous. Specimens were found 

 with eight nuclei (Fig. 5), or with six nuclei, four of them smaller 

 and resulting from the division of two of the nuclei of the four- 

 cell stage, with the other two larger and still undivided (Fig. 19). 

 The plasmodium at this stage measures from 3.7 to 4.0 micra in 

 width to from 4.2 to 5.3 micra in width. Divisions are multiplied 

 until the multi-nucleate spherical stage is attained (Figs. 6, 20, 

 21). These spheres measure from 5.3 to 8.8 micra in diameter. 



The nuclei of the spheres just described stain uniformly black. 

 The next stage in the cycle is the transformation of these nuclei 

 into spores. In this process they enlarge somewhat, stain less 

 intensely, and form a definite spore wall (Figs. 7, 22). Some of 

 them show a thickening of the wall on one side (Fig. 22). These 

 spores usually vary in size from i.o to 1.6 micra in diameter. 

 The larger spore in Fig. 22 is exceptionally large, measuring 

 about 1.8 micra. Occasionally spores no larger than 0.5 micron 

 in diameter are found. 



A comparison of Sphasrita endamccbx with the Sphxrita from 

 Amoeba Umax so carefully described by Chatton and Brodsky 

 (1909) shows certain fundamental differences. First, the nuclei 

 of the young uninucleate forms are comparatively large and 

 central in S. endamoebx. Those from Amceba Umax were puncti- 

 form and excentric. These distinctions alone are sufficient to 

 justify a distinction between the two species. Second, not all 

 the nuclei of 5. endamcebx develop simultaneously into spores, 



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