GAMETOGENESIS OF SACCOCIRRUS 27 



or less closely to a body which under certain conditions becomes 

 densely black in Cajal's formalin silver-nitrate technique for 

 the Golgi apparatus. During mitosis Carleton has shown that 

 the argentophil core which he calls a nucleolinus (Haeckel) 

 does not lose its individuality but divides, and may be found 

 among the two chromosome groups of the telophase. I have 

 been enabled to go through the preparations made by Carleton 

 and can vouch for the correctness of his description; more- 

 over, I possess preparations of the gut-cells of Saccocirrus, 

 of the follicle-cells of Stenobothrus, and of many tissues in 

 Eana, all of which show a typical nucleolinus. What is very 

 important is that Carleton has shown that the nucleolinus may 

 be associated with either a ' karyosome ' or a ' plasmosome ' 

 type of nucleolus. These remarks will serve to indicate the 

 importance of work carried out on the nucleolinus, especially 

 with Cajal's formalin silver-nitrate method ; Da Fano's cobalt- 

 nitrate method also serves to bring out the nucleolinus in some 

 forms. 



Interpreting the work of Carleton on the nucleolinus, and 

 also in the light of Cajal's figures of various mammalian 

 tissues and my own materials of invertebrates, I believe that 

 the nucleolus, term used generally, might be morphologically 

 independent of the chromosomes during the germ-cell cycle ; 

 the nucleolus during interkinesis might exist as a compound 

 body consisting of a core which is argentophile and sometimes 

 chromophile to other stains, and this core might act as the 

 centre for the proliferation of a more extensive body which 

 functions as the plasmosome or karyosome of the ' resting ' 

 nucleus ; furthermore, during mitosis this outer region pro- 

 liferated from the argentophil core possibly becomes lost, to 

 be reformed in the next interkinesis. How far these suggestions 

 will be found correct is impossible to say at present, but many 

 of the facts we know now point in the direction I have indicated. 

 Moreover, this view would coincide with the already-formed 

 theories of the chromosome worker. 



The nature of the nucleolus is mainly proteid, maybe even 

 in some cases nucleo-proteid, but its functions appear to be 

 different from those of the chromosomes. The nucleolus, like 



