536 MR. A. LISTER OS THE DIVISION OF 



the contents of a sporangium was smeared on a thin cover-glass 

 every half-hour, and after 6 o'clock every quarter of an hour, and 

 placed in Flemming's fluid. A check staining with acetic gentian- 

 violet was made on each occasion to note any change that might 

 occur. At 4.15 in the morning there was an indication of the 

 formation of capillitium by the appearance of vacuolar spaces in 

 the plasma, in which granules of lime, which abound in the Plas- 

 modium, were seen to be collecting. The nuclei had the same 

 character as in the streaming plasmodium and, with the exception 

 of the further development of the capillitium, there was no appa- 

 rent difference in the successive stainings until 11.37. At this 

 period the gentian-violet stain showed a changed appearance in the 

 nuclei, suggesting that the " coil " stage had been reached. From 

 11.45 to 12.45, w r hen spores had formed, smears were taken every 

 two minutes. I have 37 stainings taken during this hour, and, 

 with the exception of two which show only spores, we have in 

 these mountings many thousands of nuclei in every stage of 

 karyokinetic change. Four hours later the sporangia under the 

 bell-jar were black from the dark-w r alled spores. 



Rosen, in the paper before alluded to, describes his investi- 

 gations relating to Fuligo and Lycogala, in which he observes 

 that shortly before the formation of the spores a nuclear plate is 

 formed, and that this plate divides and the two halves separate ; 

 but he did not succeed in making out the presence of the spindle- 

 fibres. He agrees with Strasburger in supposing that there is a 

 simplification in the karyokinetic process in Mycetozoa as com- 

 pared with that observed in higher forms. He thinks the coil 

 stage may be absent in this group, and further states that the 

 smaller the nucleus the more simple is the process. I cannot 

 think that this view f is borne out by the preparations of the species 

 I have examined. We have, in the first place, the change from 

 the condition of the nucleus with distinct nucleoli lying in a close 

 reticulum to that of a more uniform structure in which no 

 nucleolus can be detected ; we then see the chromatin matter 

 withdrawing from the nuclear wall, and presenting much the ap- 

 pearance of a continuous coil (PI. XXXV. fig. 4) ; this is followed 

 by the formation of the nuclear plate, in which about eight seg- 

 ments may be counted when seen in profile ; from this plate the 

 spindle-fibres can be clearly seen converging towards a point at the 

 opposite poles : then we have the stage when the nuclear plate 

 ha,s divided, the spindle-fibres are seen to connect the separated 



