THE H^MOFLAGELLATES. 235 



has been described, either as exteuding to the distal end of 

 the undulating membrane (i. e. as far as the flagellum acts as 

 a border to the same [fig. 23 c]), after which the two halves 

 separate ; or, as being practically limited to the root-portion, 

 which becomes thickened and then divided, one half breaking 

 away as a new short flagellum, the further growth of which 

 is basal and centrifugal (fig. 27 d). As above stated, however, 

 Schaudinn finds that, in Trypanomorpha noctuae, the 

 whole of the flagellum, etc., is developed independently 

 from the daughter-kinetonucleus and laid down alougside 

 the old locomotor apparatus ; moreover, Prowazek (1. c.) 

 maintains that this is also the case both in Trypanosoma 

 lewisi and T. brucii.^ It appears uncertain, therefore, 

 whether splitting of the flagellum really occurs." However 

 this may be, one of the resulting flagella (the new one) is 

 often at first shorter than the other, either possessing only 

 a small free portion (fig. 23 c) or none at all ; more par- 

 ticularly is the latter the case when rapid successive multi- 

 plication has been going on. 



Cytological details with regard to the behaviour of the nuclear apparatus, 

 such as are given by Schaudinn (1. c), are only to hand in one or two cases. 

 For the most part, nuclear division has been, so far, described as consisting 

 simply of aggregation of the chromatin at either end, followed by con- 

 striction in the middle and subsequent separation of the two halves as 

 daughter-nuclei. Wasielewsky and Senn (120), however, mention and 

 figure a kind of simple mitosis in a case of multiple division in T. lewisi. 

 Prowazek (1. c.) has described the process in T. brucii more fully. The 

 kinetonucleus becomes thickened and more or less spindle-like (fig. 24 a) 

 Subsequently it assumes a dumb-bell-like appearance, and the two halves 

 become further separated, remaining connected only by a long thread (b) ; 

 this sometimes shows a delicate thickening (apparently divided in the fig.) 



^ McNeal (74) is of the same opinion with regard to the multiplication 

 of T. brucii in cultures. 



^ The same applies equally, of course, to the formation of the undulating 

 membrane. If the flagellar border splits, the membrane doubtless divides 

 also; but where the flagellum is a new development, tlie undulating mem- 

 brane is so too. Certainly, to judge from many of the published figures 

 (cf. also some of Prowazek's), one would conclude that actual splitting of 

 the flagellum is taking place. 



