Lewton-Brain — Cor dy ceps ophioglossoides ( Ehrh .). 523 
the perithecium ; young ones are continuously being pushed 
up between the bases of the older ones. 
The youngest ascus I have observed is shown in Fig. 3, 
which represents the upper two- thirds of the ascus. It con- 
tains already about half a dozen nuclei, irregularly distri- 
buted. The protoplasm is finely granular, and stains darkly 
with haematoxylin ; a cap is present even at this stage. I 
have obtained all stages intermediate between this and the 
mature ascus. 
The nuclei divide repeatedly, and the resulting nuclei dis- 
tribute themselves quite irregularly in the protoplasm of the 
ascus. Successive stages in this process of division are shown 
in Figs. 5 a , b, c , 6, 7, and 8. Figs. 5 a , b , and c show some of 
the nuclei in the process of division. I was, of course, unable 
to observe any karyokinetic figures. The protoplasm through- 
out these divisions remains finely granular, and continues to 
stain darkly with haematoxylin. During this period of nuclear 
division the ascus increases slightly in breadth and consider- 
ably in length. 
At the end of this period we have then the long, narrow 
ascus, tapering towards the base, and with a well-marked cap 
(Fig. 12) stretching the greater part of the length of the peri- 
thecium. It is somewhat twisted, so that it is rare to get any 
considerable length of an ascus in one section, even though 
the section be median to the perithecium ; moreover, the large 
number of asci in a perithecium renders it almost impossible 
to piece together the whole of any single ascus from a series 
of sections. The protoplasm is dense, and shows no traces of 
divisions. Scattered irregularly about in the protoplasm are 
immense numbers of small, roundish nuclei (Figs. 7 and 8). 
After divisions have ceased, the nuclei become arranged in 
rows longitudinal to the long axis of the ascus. Owing to the 
large numbers of nuclei and the narrowness of the ascus, this 
does not involve any great change of position for the nuclei, 
as may be seen from Fig. 8. Eight longitudinal rows are 
formed, of which three are usually seen in section. 
Following this rearrangement, longitudinal lines of division 
