Dale . — Observations on Gymnoascaceae. 581 
usually, but not always, near the apex (Fig. 31 b). The nuclei 
now increase in size, and the protoplasm also seems to become 
more abundant, so that the vacuole disappears and the 
developing spores fill the ascus (Fig. 31 c ). 
At different stages in their development the young spores 
behave very differently towards stains. At first they are oval 
in shape and, with the toluidine blue method (cp. p. 576), their 
nuclei stain a deep pink with the eosin. In some young spores 
there are two deeply staining bodies (Fig. 33 a ) ; in others 
a single elongated body, which in some cases is thickened at 
each end (Fig. 32 b), and in other cases is thickened in the 
centre (Fig. 32 c). These observations suggest a nuclear 
fusion in the spores like that in the spores of Uredineae. At 
a later stage the spores become larger and rounder, and their 
contents stain more diffusely and not so deeply (Fig. 32 e). 
Finally the spores attain to their full size and become spherical. 
In this stage they remain colourless with the toluidine blue 
method (Fig. 32 f). 
With the triple stain, on the other hand, the ripe spores 
stain more deeply than those which are still immature. They 
become strongly coloured by the safranin. 
Amongst the ascogenous hyphae are a few thinner, slenderer 
hyphae, which often contain many small nuclei. These hyphae 
appear to be vegetative, and may either be those of the ordi- 
nary mycelium or those arising from the base of the coil. 
Some of the ordinary vegetative hyphae become changed 
into the thick-walled hyphae described above (p. 576, Fig. i), 
which envelop the asci. 
II. Gymnoascus setosus. 
The original material of this species also consisted of ripe 
ascospores and vegetative hyphae. The hyphae were so thick- 
walled, and coloured such a deep brown, that, except at their 
ends, they were opaque (Fig. 33). Their branching is pecu- 
liar, and both the main and the lateral branches end in sharp 
spines or bristles. They occurred in masses enclosing numbers 
of spindle-shaped colourless spores, either isolated or still 
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