14 H. MARSHALL WARD. 



minute pore should escape observation from without is not remark- 

 able : the reflection of the light from the black shining outer cells 

 might easily obscure it. The general structure of these walls has 

 already been described, and figure 34, drawn from an extremely for- 

 tunate and very thin section, shows the details. 



The very young ascus presents no features of importance to distin- 

 guish it from that of many other pyrenomycetous fungi. In its earliest 

 state it is recognisable as a, single thin-walled, club-shaped cell, taper- 

 ing to a point at the lower attached end, and filled with finely granular, 

 yellowish protoplasm (see fig. 37 a.) : sometimes a small pale, refrac- 

 tive nucleus-like point is seen in the protoplasm. As the young ascus 

 grows longer, and its protoplasm increases in quantity, a fine, sharp 

 division line makes its appearance somewhat oblique to the long axis 

 of the whole (fig. 37, c.) ; this is soon followed by a second, similar 

 longitudinal division, in a plane at right angles to the former (fig. 

 37, d.), and four well-defined masses are thus marked out. These, the 

 young spores, do not include the whole of the protoplasm (fig. 37, 

 d and/.), but lie in a scanty matrix of granular matter, closely ap- 

 posed face to face, and following the curve of the wall of the enlarging 

 ascus on their outer walls. 



As the four, almost fusiform young spores increase in size, and 

 acquire more distinct membranous envelopes, they come to lie some- 

 what more loosely in the cavity of the ascus, and may cross one another 

 in accommodation to the space at disposal. Then appear cross-septa 

 (fig. 37, e., /.), dividing the material of the spore into a number of 

 compartments varying from three to five — or, in one case, a single 

 septum only is formed — and vacuoles and granules appear in the 

 hitherto almost homogeneous contents. As the spores ripen, their 

 cross-septa become more firmly marked, their outer walls thicker, and 

 gradually brown or nearly black in colour, like the hyphse of the de- 

 veloped mycelium ; the side walls of the separate compartments also 

 become bulged out slightly, giving the mature spore the appearance of 

 a long oval body, constricted at intervals (see fig. 39). Very com- 

 monly one or two oily -looking drops accumulate in the compartments' 

 of the ripe spore. 



Such is the typical mode of development of the perithecium, asci 

 and spores. I have found no modifications of importance from a 

 morphological point of view ; it should be recorded, however, that the 

 number of spores in the ascus varies from two to eight. Sometimes 





