DIVISION OF COLLAR-CELLS OF CLATHRINA CORIACEA. 613 



is a cliromatic body, which may be denoted temporarily by 

 the symbol N, situated usually in or near the middle of the 

 cell-body, aud in no special connection with the flagellar 

 appai-atus. Secondly, there is a second chromatic body, 

 which may be denoted by the symbol n, distinctly con- 

 nected with the flagellum or flagella, when they are present, 

 and apparently kinetic in function. lu the genera Try- 

 panosoma, Herpetoraonas, Leishmania, and Cri- 

 thidia, N is always much larger than n, but in Trypano- 

 plasma the reverse may be the case. Finally, the flagella 

 arise, probably in all cases, from basal granules, which are 

 often very minute and exhibit staining reactions quite 

 diffei'ent from either N or n. 



According to the nucleai- theory of the centrosome advo- 

 cated by Hartmann and Prowazek, these three parts of the 

 trypanosome body are to be interpreted and named as 

 follows : N is the trophic nucleus, while n represents the 

 second nucleus of kinetic function, in other words, the cen- 

 trosome, which, since it controls the activities of the flagellar 

 apparatus, is to be termed a blepharoplast. The basal granule 

 is a mere thickening of the proximal end of the flagellum, of 

 no special significance, or at most representing a centriole. 

 Thus a trypanosome would represent the ideal binucleate cell 

 of Hartmann and Prowazek in a very primitive state. 



An interpretation of the trypanosome body, quite different 

 to that of Hartmann and Prowazek, has been advocated by 

 one of us (12), which may be briefly stated as follows: iVis 

 a trophic nucleus, which contains its own centrosome or 

 division-centre in itself; n is a distinct kinetic nucleus, a 

 specialisation of the nuclear apparatus for a particular func- 

 tion ; it has nothing to do with a true centrosome, though it 

 may, like the trophic nucleus, contain a body of this kind, nor 

 is it to be regarded as a blepharoplast, a body which is repre- 

 sented by the basal granule of the flagellum.^ 



' It is not our purpose here to summarise the various views that 

 have been put forward with regard to the morphological interpretation 

 of the trypanosome-body, but only to select two which show in sharp 



