﻿Try panosome found in Pontobdella. 101 



any division of individual chromosomes, and, correlated with 

 this, there is no trace of mantle fibres. 



The karyosome appears to exercise certain kinetic or 

 centrosomal functions, but is not, in my opinion, respon- 

 sible for the whole of the mitotic fibre apparatus. It is not 

 a case of an amitotic division of the nucleolocentrosome such 

 as Keuten has described in Euglena, bringing about a 

 division of the surrounding chromatin ; but rather a set 

 of fibres arising much as in the case of the metazoan 

 mitosis, only here the process occurs inside instead of 

 outside the nucleus. 



In the parasite under discussion, it is difficult to make 

 any statement as to whether the centrosomal functions are 

 concentrated into a definite granule, as in the case of 

 Trypanomorplia nochta:, or are more or less diffusely present 

 in the karyosome. The granule occasionally found within 

 this structure is too indefinite and inconstant to be able to 

 make any statement concerning it. 



The division of the kinetonucleus, which is always a 

 transverse one at first sight, suggests amitosis. Further 

 study, however, shows that there is here also a simple kind 

 of mitosis, although the details are extraordinarily obscure. 

 The kinetonucleus, as already stated, is composed of several 

 elements, and it appears to contain two substances, one of 

 which stains very much more deeply with the red element of 

 the Eomanowsky stain than the other (Figs. 31-34). 



The earliest sign of division is that the deep staining 

 chromatic substance becomes arranged in two little parallel 

 rods, one at either side of the kinetonucleus. Each of these 

 bears the appearance of being slightly split transversely to 

 the axis of the little rod (Figs. 33, 34, 43, and 49). These 

 two rods appear to be connected along the top and bottom 

 by two slender vertical bars, thus the oblong shape of the 

 kinetonucleus is still preserved. The remainder of the 

 structure is filled with a brighter red substance. There 

 then appears to be an increase in the length of the two dark 

 staining rods, until these are each as long as the ordinary 

 kinetonucleus. Exactly how this is effected I do not know. 

 Presently the two new blepharoplasts move slightly apart. 



