TRICHOMONAD FLAGELLATES. 333 



in the light of our data which are more complete than those at their 

 disposal. If preparations are not adequately destained irregular 

 pictures such as they figure may be abundant. We have found the 

 alcoholic iron haematoxylin method particularly helpful in giving 

 clean cut nuclear preparations. The fact that the constricting nu- 

 clear membrane in the telophase simulates amitotic conditions may 

 be dismissed as without significance for amitosis in view of the differ- 

 entiation and behavior of the chromosomes in such nuclei in tricho- 

 monads. 



The theoretical importance of the critical examination of all re- 

 ported cases of amitosis among the Protozoa is great, not only as to 

 the primitiveness of this form of cell division, but also as to its normal- 

 ity, since all trophozoites are, in so far at least as a priori considera- 

 tions are concerned, potential gametocytes or their ancestors. Since 

 chromosomes are differentiated in trichomonads the significance of 

 the occurrence or non-occurrence of amitosis is thereby increased. 

 We believe the interpretation of division by amitosis to be without 

 adequate foundation. Should undoubted cases of it be found, it 

 will be desirable to know the fate of the trophozoites thus produced. 



The existence of chromosomes has been somewhat problematical 

 in the trichomonads, and their number variously interpreted. Dobell 

 (1909) finds six chromatin masses in Trichomastix hairachorum, but 

 states that " they cannot justly be called chromosomes." Martin and 

 Robertson (1911) do not regard them as chromosomes, while Kuc- 

 zinski (1914) affirms their occurrence in Trichomonas caviae, but re- 

 gards eight as the normal number basing his interpretation on stages 

 prior to the metaphase in which later stage he finds four plurivalent 

 chromatin masses. We have given a different interpretation to our 

 findings in the larger and clearer T. augusta. The fusion of smaller 

 masses of chromatin or chromomeres (or the chromosomes of Kuc- 

 zynski) results in the formation of chromosomes which then split 

 longitudinally before entering the equatorial plate. We have dis- 

 tinguished five chromosomes rather than four, though the fifth, a small 

 one, is often difficult to find. Many of Kuczynski's figures of the 

 equatorial plate and adjacent stages show five rather than four chro- 

 mosomes, so that we are inclined to think that this species also has 

 five chromosomes and that the process of chromosome organization 

 is essentially similar in his material and ours. 



The fact that the number of chromosomes is five, an odd number, 

 raises the question as to whether or not there may also be individual 

 lines of asexual descent with four or possibly six chromosomes and 



