PLATE 3 



Figs. 24-32. Multiple fission; somatellas. (Fig. 24). An early stage in the 

 formation of a somatella. The flagellate is rounding up, and the flagellum is 

 entirely intracellular. No indications of division of the nucleus, parabasal 

 body, or the blepharoplast are present. 



Fig. 25. A somewhat different type of rounding up. The attenuate anterior 

 and posterior ends are being wrapped about the body. The nucleus has begun 

 to constrict or to divide by a process of primitive promitosis. The blepharo- 

 plast and parabasal have not yet begun to divide. 



Fig. 26. A more advanced stage in the formation of the somatella. The 

 flagellum of the rounded up flagellate is protruding and both the nucleus and 

 blepharoplast, together with the parabasal body, have divided. The new 

 daughter-flagellum is not yet visible. 



Fig. 27. A sphere, or somatella, still more advanced in its development. 

 Not only have the blepharoplast, parabasal body, and the nucleus divided but 

 the new outgrowth of the second flagellum from the daughter-blepharoplast is 

 clearly visible. 



Fig. 28. A spherical crithidia showing a repeated process of division on 

 the part of the nuclei and parabasal bodies. Three parabasal bodies and two 

 nuclei are present. There are possibly indications in one of the nuclei wherein 

 the chromatin has been divided that another division was about to occur. 



Fig. 29. A sphere, or somatella, without protruding flagella, containing at 

 least four definitely outlined merozoites. The nuclei, parabasal bodies, nuclear 

 rhizoplasts, and the outgrowths of the flagella are clearly visible. 



Fig. 30. A densely stained, small somatella containing four relatively large 

 merozoites which are beginning to elongate. 



Fig. 31. A sphere, or somatella, breaking up and the merozoites about to 

 escape. The destruction of the sphere has occurred later than usual and the 

 merozoites have become almost mature flagellates. All nuclear structures are 

 deeply stained, owing to the thickness of the sphere. 



Fig. 32. An exceedingly large sphere, comparatively, showing many pro- 

 truding flagella. Here again the nuclear structures are deeply stained because 

 of the thickness of the sphere. The exact number of merozoites cannot be 

 determined, but approximately twenty-four nuclei and parabasal bodies can 

 be counted. 



Figs. 33-38. Binary fission. (Fig. 33.) A small spherical crithidia under- 

 going binary fission. The nucleus has divided but the blepharoplast and para- 

 basal body show no indications of fission. 



Fig. 34. Binary fission, in which the blepharoplast and parabasal body have 

 divided but the nucleus has not yet divided. A flagellum from the daughter- 

 blepharoplast has already grown forward. 



Fig. 35. Binary fission taking place in a developing crithidia. Both the 

 nucleus and parabasal body have divided, and a new flagellum can be observed 

 growing from the daughter-blepharoplast. 



Fig. 36. Simple binary fission; blepharoplast, parabasal body, and nucleus 

 have divided. The chromatin in the nuclei is peripheral, about the membrane. 



Figs. 37, 38. A more advanced stage of binary fission, showing in addition 

 to the division of the blepharoplasts, parabasal bodies, and nuclei a cleavage 

 in the cytoplasm to form two crithidias in each case. 



Fig. 39. Intracellular multiple fission: one of the many infected cells 

 from the "crop" of Euryophthalmus convivus. This cell is in a degenerating 

 condition. The nucleus stains a blue-gray color in iron-haemotoxylin. There 

 are at least three and possibly five intracellular infections by C. euryophthalmi 

 in this cell. There are approximately seventy parasites within this cell: (a) 

 A group of parasites of two sizes, small oval forms, non-flagellated and elon- 

 gated Crithidia. Nuclei of all crithidias are diffuse, possibly due to thickness 

 of smear. Nucleus and parabasal body readily observed but the other organ- 

 elles are not always clear, (b) Another group evidently the result of a process 

 of intracellular multiple fission, (c) Similar to b. Circular cavity about these 

 non-flagellated crithidias may indicate the outline of a former somatella 

 wherein plasmotomy has occurred early, (d) Elongate merozoites probably 

 resulting from another intracellular somatella. Plasmotomy has occurred and 

 the merozoites are about to make their way out of the host cell, (e) A scattered 

 group of oval merozoites. Considerable variation in size is noted. Parabasal 

 body, nucleus, and intracellular portions of flagellum clearly shown. (/) A 

 mature merozoite making it way out of the host cell. The non-flagellated, or 

 posterior, end directed first. 



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