312 DR. T. GOODEY ON 



than the kaiyosome of the trophonucleus. It has no nuclear 

 membrane and is situated towards the ventral surface, close to 

 the upper end of the mouth-depression. Its position can readily 

 be made out in figs. 1 & 2. 



The two flagella arise close to the anterior surface of the 

 kinetonucleus from very indistinct blepharoplasts. The anterior 

 flagellum is the shorter of the two, the posterior one being two 

 or two and a half times its length. The organism ingests bacteria, 

 which no doubt serve as a source of food, for the protoplast is 

 often packed with cocci and other small forms of bacteria. 



(b) Reproduction. 



The first indication of approaching division which I have been 

 able to find is the doubling of the anterior flagellum (fig. 4). At 

 this stage no change is visible in the appearance of the nuclei. I 

 am unable to say how the flagella become duplicated, but, judging 

 from the fact that 1 have found no organisms showing protrusions 

 like flagellar buds, and also that when the flagella become doubled 

 the members of each pair are equal in length, I am inclined to 

 the view that the original flagella split longitudinally. 



The posterior flagellum becomes doubled later than the anterior 

 one, and at this time the trophonucleus shows a marked change 

 in appearance. The karyosome becomes much reduced in volume 

 and divides into two equal parts, whilst at the same time the con- 

 necting strands between it and the nuclear membrane disapjjear. 

 The nucleus elongates a little and stains rather more deeply, 

 doubtless owing to the liberation of a chromatinic substance from 

 the karyosome (figs. 5 & 6). Irregular gi-anules of chromatin now 

 appear at the periphery of the nvicleus as the result of further 

 fragmentation of the karyosome, and become concentrated towards 

 the equatoi'ial region. This particular stage is veiy difficult to 

 determine, and I cannot say whether an equatorial plate is pro- 

 duced. So far as I can ma.ke out, there is merely an aggregation 

 of chromatin granules on the surface of the nucleus in this region. 

 These granules finally concentrate into four principal larger ones, 

 which are arranged in two pairs. The stage figured on fig. 9 shows 

 them apparently connected by two crossing strands. The nucleus 

 ijow elongates, each end being somewhat pointed, and each pair 

 of granules becomes drawn towards opposite ends of the nucleus. 

 These stages are shown in figs. 10, 11, & 12. Soon after this a 

 constriction appears in the middle of the nucleus, which now 

 becomes rather dumb-bell-shaped (fig. 15). At about the same 

 time, or even earlier, the four granules of chromatin begin to 

 show signs of breaking down, and also stain less intensely 

 (figs. 13-16). The constriction at the centre of the nucleus 

 becomes carried still further, until two triangular daughter- 

 nuclei are formed, each of which contains rather faintly staining 

 chromatin granules. I have found it impossible to trace the 

 later stages in the reoi'ganisation of the daughtei-nuclei, owing 



