304 KOFOID AND SWEZY 



with apparently but a single undulating membrane, but with two 

 nuclei, two blepharoplasts with flagella, and two chromatic basal 

 rods, a paradesmose between the blepharoplasts, and apparently one 

 axostyle. From each blepharoplast, there arises a stout "organe 

 parabasale de Janicki" parallel to the chromatic basal rod. We 

 interpret this as an early stage in multiple mitosis in the initial phase 

 of a second mitosis and the two "organes parabasales" as new out- 

 growing parabasals indicative of a coming second mitosis. That is, 

 they are parabasals, but so are also the chromatic basal rods of which 

 they themselves are only the initial stages. It is apparently to this 

 young parabasal that Alexeieff referred in an earlier paper (1909a) 

 but regarding it (baguette recourbee) at that time as a characteristic 

 of the Trichomonas of salamanders as contrasted with those of frogs, 

 and as a part of the undulating membrane. He makes, however, no 

 further reference to this interpretation in later papers. 



In a series of preparations of this species we have traced nearly all 

 stages of mitosis, and in hundreds of individuals find no trace of para- 

 basals as stout as those figured by Alexeieff, but only somewhat more 

 slender ones at this stage of outgrowth. We conclude therefore that 

 normally there is regularly no structure so large as Janicki and Alexeieff 

 figure as their parabasal and that this structure, large or small, is the 

 outgrowing new chromatic basal rod (PI. 2, Figs. 11-16) which they 

 interpret with some adjacent chromatic granules as the sole and only 

 parabasal. If this be true, Janicki's (1911), Alexeieff 's (1913), and 

 Kuczynski^s (1914) interpretation is then only partially correct. 

 The organ which they call the parabasal is only the first step in the 

 origin of the new parabasal in the prophase of mitosis. The true 

 parabasal includes both this and the organ which is regarded by them 

 as distinct, namely the chromatic basal rod of the undulating mem- 

 brane, and the inconstancy and variation noted by them is explained 

 by the fact that they were dealing with a growing organelle.^ 



1 In a paper received after the completion of this manuscript Janicki (1915) 

 repeats his earher figure of Trichomonas augusia showing the stout " parabasal," 

 and adds an incomplete new one (his text figure 13) showing what we interpret 

 to be the paradesmose, also the slender parent parabasal, and a stout daughter 

 one. It is evident from figures and context that he has not worked over an 

 extensive series of preparations of this genus. He regards T. augusta as possi- 

 bly the same as T. bntrachorum to which species he states his material to belong. 

 We find both species, and regard them as distinct, the latter havmg food 

 vacuoles with contents, a more slender axostyle, and a very general absence 

 of both axostylar and cytoplasmic chromidia. In this species whose mitosis 

 we have also followed, the chromatic basal rod or parabasal in our sense, is 

 even more slender than it is in T. augusta. We have not, as yet, seen the 



