1920] Kofoid-Swezy: Morphology and Mitosis of Chilomastix 119 



ACKNOWLEDGMENTS 



Acknowledgments are made to Lt. Col. E. H. Schorer, M.C., 

 U.S.A., in charge of the Army Laboratoi-y, for his efforts to provide 

 facilities and staff for the work, and to 2nd Lt. S. I. Konihauser for 

 his technical aid in making preparations upon which this work is 

 based. 



A grant from the Division of Medicine and Related Sciences of 

 the National Council of Research made possible the cooperation of the 

 junior author. 



MORPHOLOGY 



The Active Flagellate 



The shape of the body of Chilomastix is normally elongate pyriform, 

 with the broad end anterior and the sides more or less convex, accord- 

 ing to the degree of extension or contraction. Its length is generally 

 two to four times its greatest width which is 0.2 to 0.3 of the total 

 length from the anterior end. The anterior end is rather broadly 

 rounded, sometimes flattened dorso-ventrally, and the curvature of 

 the two sides is dissimilar. This dissimilarity is masked in the other 

 irregularities due to the spiral groove. This asymetry is fundamental ; 

 it is caused by the relative positions of nucleus and cytostome, but is 

 variously modified by the movements of the latter and by the torsion 

 of the body. In ventral view (fig. A) the cytostome lies to the right 

 side of the body (left of the figure) and the nucleus to the left. These 

 relations persist in the cyst and at mitosis. 



Posteriorly the body contracts rather abruptly into a short taper- 

 ing tail, whose length is 0.2 to 0.3 of the total length. Tliis tail may 

 stretch out in a long thread, sometimes nearly as long as the body, 

 when autotomy of the cytoplasm is in process, showing its great 

 plasticity. It is apparent that the cytostome of Chilmnastix is mor- 

 phologically more highly differentiated than that of Trichomonas, 

 Eutrichomastix, or Emhadomonas. Specialization in function may 

 well attend this structural development. Adhesion of the parasite 

 to the intestinal wall of the host by Giardia, and possibly also by 

 Chilomastix, is certainly one factor of no small clinical significance 



