STUDIES ON CEYLON H/EMATOZOA. 745 



difficult to deuioustrate ; irou-hcBmatoxyliu films or those 

 counter-staiued with eosia ai-e the best for this purpose. The 

 capsule never persists after the parasite has escaped, iu fact 

 it seems that iu this case the envelope may be said to dis- 

 integrate rather than to be shed in the usual way. The 

 capsule is to be seen quite clearly iu the live state in in- 

 dividuals from the crop of the leecli, especially at the time 

 when the blood-corpuscle has been already digested away, 

 but before the parasite has passed down to the intestine, 

 where it becomes motile. 



The protoplasm is delicately alveolar, and is sometimes 

 slightly granular ; chromatoid particles outside the nucleus are 

 very rare, and this form does not show the curious eosinophile 

 inclusions found, for instance, in H. vittatte (11). The 

 nucleus consists, ;is a general rule, of a number of isolated 

 chromatin granules arranged, often rather symmetrically, 

 round a small central body (see figs. 1-3). The peripheral 

 grains of chromatin may be connected by strands with the 

 central granule. This central granule cannot be called a 

 karyosome iu anything approaching the same sense in which 

 this word is applied iu protozoan literature generally. In the 

 nucleus of this hgemogregarine it is only the position that 

 marks off the central body from the peripheral chromatin 

 granules ; it is iu no way distinguished from them iu size or 

 staining reaction, and iu those cases where the chromatin 

 granules are less regularly arranged (fig. 9a) it is quite impos- 

 sible to pick it out with certainty. Nevertheless, it appears 

 to me to be of a diiferent nature from the other nuclear 

 elements, iu so far that, in the very primitive nuclear division, 

 it seems to form a kind of centrodesmose. Not infrequently 

 the peripheral chromatin granules are joined to one another, 

 a chroinatin ring being thus formed all round (see figs. 2, 5. 

 and 8). It must not be supposed that this chromatic ring is 

 truly a nuclear membrane ; it takes the chromatui stains 

 deeply, and assumes a bright red colour with Twort's stain. 

 It is thus in sharp contrast to the green membrane found by 

 this method round the nucleus in, for instance, some trypauo- 



