SOME OBSERVATIONS ON A NEW GREGARINE. 275 



toxylin and eosin, the centrosome is differentiated into a 

 faintly stained peripheral portion — the centrosphere — in the 

 centre of which is a black centriole ; this also shows in fig. 20 

 stained in the same manner. 



In studying the various generations of daughter-nuclei 

 several interesting points demand attention. They present 

 an infinite variety as regards the arrangement of their 

 chromatin. Except when actually drawn out into a spindle 

 they are invariably vesicular in structure; and, in the great 

 majority of cases, in the earlier stages at any rate, they 

 contain a distinct karyosome. This is of interest in that in 

 l^jchmomera hispida, described by Schellack (17), where 

 the karyosome invariably appears in the daughter-nuclei, 

 its origin is referred to the unpaired chromosome of this 

 form, which chromosome thus has a function allotted to it. 

 In Sty lorhynchus, which also shows this phenomenon, there 

 is, however, no such unpaired chromosome (11). The fate of 

 these daughter-karyosomes in Metamera schubergi is not 

 certain. The corresponding spindle figures do not show any 

 traces of karyosome fragments in their neighbourhood. On 

 the other hand, in such stages as shown in figs. 19 c and d, 

 where the nucleus is on the point of elongating into a spiudle, 

 the karyosome seems to be extruding part of its substance. 

 IE this is so, the process is one of immediate and complete 

 solution, and not exactly parallel with the behaviour of the 

 adult karyosome. It must be clearly understood that, as the 

 iigures show, a karyosome cannot be always with certainty 

 identified in these daughter-nuclei. Thei^e are always present 

 masses of chromatic substance of varying sizes, and their 

 arrangement is at times such as to make the distinction 

 impossible. In the daughter spindle-figures, as with the first 

 division, there is again no definite chromosome formation. 

 The chromatic elements are sometimes discernible as streaks 

 and granules near the poles o£ the spindle ; sometimes the 

 deep black appearance of the spindle-fibres, alone present, 

 suggests that these latter may be conveying chron)atin in 

 very minute particles. A constant feature of these young 



