142 William J. Hodgetts. 
seconds a length equal to three times the original intact ascus 
(Fig. 4), or even longer, but under these conditions was never 
observed to discharge its spores; it gradually dissolves and the 
spores germinate in situ. During this process of elongation the 
inner coat of the ascus wall can be seen to be quite free from the 
outer cuticular coat in the neighbourhood of the upper part of the 
latter at any rate; lower down the two coats are firmly joined. 
The free upper part of the outer membrane becomes slightly 
retracted, and usually shows a few transverse folds or wrinkles. 
When the perithecia are simply crushed under a cover-glass and 
the asci expelled, the outer coat of the ascus wall is frequently 
observed to have been ruptured by one or more annular splits as 
shown in Fig. 5, the inner coat swelling and emerging in various 
irregular ways. 
If a few mature perithecia are mounted whole in water, and 
observed in profile, after an hour or so the successive emergence 
through the ostiole of the inner gelatinous coats of the asci, 
each containing eight spores in its upper part, can readily be 
observed. Each elongates, sometimes at a very rapid rate, to 
about 0-3 mm. or even more beyond the orifice of the perithecium ; 
its wall can be seen to be thin and tightly stretched. However, 
under these conditions the spores were never seen to be forcibly 
ejected; the gelatinous tubes after elongating to a considerable 
length apear to break away at the base, since each is usually 
observed to suddenly collapse, while the spores being relieved from 
the pressure which kept them in the apical region of the tube 
suddenly shoot down the latter and come to lie scattered lower 
down the ascus tube, although still outside the perithecium. The 
numerous collapsed asci with their spores eventually form a tuft 
radiating from the ostiole of each perithecium, and finally, by 
dissolution of the walls of the tubes the spores are set free in the 
water. This mode of spore dispersal probably takes place in 
nature when the perithecia are wetted with rain or dew. 
So far we have spoken of the behaviour of the asci when 
immersed in water, and have observed how the ascus dehisces and 
the inner wall with the spores elongates, but if perithecia are kept 
in a moist atmosphere, that is, under somewhat more normal con¬ 
ditions, then a very different process takes place. When pieces of 
nettle stems with numerous mature perithecia attached are placed 
in a Petri dish, the bottom of which is covered with damp blotting 
paper, and left for 24 hours, the under side of the lid of the 
dish, several millimetres above the upwardly directed ostioles, will 
be found to have numerous spores adherent to it, thus showing 
