TRICHOMONAD FLAGELLATES 319 



It appears from our data that their separation is not an obHgatory 

 part of mitosis and that it may occur in many stages of the process. 

 It is also indicated that the blepharoplast of the trichomonads is 

 potentially, if not indeed also structurally, composed of at least two 

 parts, centrosome and basal granule, and that it is the center from 

 which extranuclear structural differentiation proceeds. 



It is a matter of considerable comparative significance that this 

 extranuclear blepharoplast and its adjacent parabasal body pass 

 through the whole process of mitosis without the remotest semblance 

 of independent mitotic behavior. Neither is in any true sense an 

 accessory nucleus. Their behavior, especially that of the blepharo- 

 plast is wholly accessory to the division of the main nucleus. There 

 is absolutely no basis in their behavior as recorded in their morphologi- 

 cal changes in mitosis for regarding either or both as a kinetonucleus 

 or as having chromatin of some subtile hereditary significance. 



The importance of this conclusion will depend in part upon the 

 correctness of our inference that the parabasal of trichomonads and 

 the kinetonucleus of trypanosomes are homologous and that the basal 

 granule at the base of the flagellum of trypanosomes is the homologue 

 of the blepharoplast, at least in part, of the trichomonads. In so 

 far as our observations are correct and the homologies suggested well- 

 founded, to that extent is doubt cast upon the mitotic interpretation 

 given to the so-called kinetonucleus of trypanosomes by Schaudinn 

 (1904) and upon the Binuclearity Hypothesis resting thereon. 



It is to be noted that during the later stages of mitosis the nucleus 

 and blepharoplast seem to lose all constant relations to the axostyle 

 and in a few cases even the blepharoplast or basal granule (PI. 2, 

 Figs. 19, 21) becomes removed from the nucleus. In these latter 

 cases the rhizoplast would either be broken or stretched out, and in 

 the former the connection of the axostyle with blepharoplast or its 

 parts, which are normally (Fig. D, 4) very intimate, must become 

 very much attenuated, as for example (PI. 2, Fig. 17) when the head 

 of the axostyle is 180° from the blepharoplast. In later stages of the 

 telophase (PI. 4, Fig. 36) the original intimate relations of blepharo- 

 plast and axostyle are restored in such a way as to suggest the per- 

 sistence of some invisible physical connection such as achromatic 

 fibers between these organs during their detachment. No objective 

 evidences of such organelles have been found in our preparations after 

 closest scrutiny. 



The nucleus during the prophase and all subsequent phases of 

 mitosis retains its nuclear membrane intact. Within it the difl'use 



