1916] Sicezij: h'iiiefoii uric lift of Flagellates 199 



In tlie opinion of the majority of investigators on these forms, the 

 process of division is initiated by the splitting of the basal granule 

 and the appearance of the new flagellum, and in this they agree with 

 what is accurately known of the higher Mastigophora. In the figures 

 of Rosenbusch (1909, pi. 25, figs. 6, 7; pi. 27, figs. 60-63, 73-74), how- 

 ever, which show a mitotic spindle in the parabasal body, no other 

 sign of division in the cell is apparent, both blepharoplast and flagel- 

 lum appearing as undivided. This makes it seem extremely probable 

 that these "spindles" are only accidental appearances of the para- 

 basal body which may be pathogenic and not of general and normal 

 occurrence, and have nothing whatever to do with division. 



On the other hand, those forms which show an undoubted division 

 of the blepharoplast and flagellum (Rosenbusch, pi. 25, figs. 12, 15; 

 pi. 27, figs. 65, 67, 76) also show what can logically be interpreted 

 only as mere pulling out and constriction of the parabasal body. This 

 interpretation agrees with what has been found by Minchin and 

 Thomson (1913) and many others in trypanosomes. As has been 

 pointed out by Wenyon (1913), "it is quite possible to pick out from 

 preparations isolated instances of nuclear division which can be in- 

 terpreted by the desiring mind as stages in a mitosis. ' ' These appeai'- 

 ances, which may be quite accidental, are apt to give a misleading 

 idea of the actual process. 



Tiypanoplasma, with its parabasal body exceeding the nucleus in 

 size, is very similar in its behavior to the trypanosomes and other 

 haemoflagellates. The division of the parabasal body as figured by 

 Martin (1910, 1913) shows a striking similarity in its behavior to 

 the same structure in Polymastix, and will be discussed below in con- 

 nection with mitosis in Polymastix hufonis. 



Prowazekia is another form in which the parabasal body has been 

 figured. The process of mitosis as described by Belaf (1914) is ini- 

 tiated, as in the majority of flagellates, by a splitting of the blepharo- 

 plast and the appearance of the new flagellum. The next step in the 

 procedure may vary somewhat, the parabasal body appearing to divide 

 before the nucleus, sometimes sumultaneously with it. The first step 

 appears to be invariable. As figured by this investigator, with the 

 moving apart of the daughter blepharoplasts (his pi. 9, figs. 18, 23, 

 25, 28), the parabasal body elongates and gradually assumes a dumb- 

 bell shape and is constricted in the middle. Following established 

 authority, however, Belaf calls this mitotic division with spindle 

 formation. His figures do not give the slightest indication of the 



