1919] McCulloch: Life Cycle of Crithidia and Trypanosoma 167 



the results of other investigators. For some time the evidence of the 

 new outgrowth was difficult to obtain (McCulloch, 1915), but very 

 clear evidence of such an outgrowth from the blepharoplast has finally 

 been discovered. Text-figure C gives a very clear picture of the origin 

 of the daughter-flagellum in C. leptocoridis. The larger size and the 

 greater abundance of crithidias undergoing this process make C. lepto- 

 coridis the most desirable material to illustrate this point. 



The importance of binary fission in increasing the number of 

 parasites in the multiplicative phase in the "crop" is not great. At 

 the present time no evidence of the process has been found in the mid- 

 stomach, which serves chiefly as a passage way for the crithidias mi- 



Fig. C. Flagellate stage of Crithidia leptocoridis to show the outgrowth of 

 the new flagellum in binary fission. X 3500. Abbreviations the same as in 

 figure A. 



grating from the "crop" to the pyloric expansion. In the pyloric 

 portion of the digestive tract, however, binary fission is of great im- 

 portance in increasing the number of crithidias, which attach them- 

 selves to the epithelial lining of the pyloric expansion. 



In connection with the process of binary fission in Crithidia eury- 

 ophthalmi another problem of interest has occurred, namely, the nature 

 of the difference, if there be any, between the division of the several 

 organelles in binary fission and the division of these same organelles in 

 the somatella. Minchin and Thomson (1915) have regarded the in- 

 crease in the number of nuclei and kinetonuclei in the spheres of Try- 



