158 FUNGI. 
sometimes two or three, develop into sporangia-bearing threads, 
while the rest are short, pointed, and form a tuft of rootlets. 
Sometimes these rootlets reduce themselves to one or more 
rounded protuberances towards the base of the sporangia-bear- 
ing threads. 
There are often also a certain number of the branches 
which had acquired a clavate shape, and do not erect 
themselves aboye the surface, instead of producing a fertile 
thread, which would seem to have been their first intention, 
become abruptly attenuated, and are merely prolonged into a 
mycelial filament. Although in other species chlamydospores 
are formed in such places on the mycelium, nothing of the kind 
has been traced in this species, more than here indicated. Occa- 
sionally, when germination is arrested prematurely, certain 
portions of the hyphz, in which the-protoplasm maintains its 
vitality, become partitioned off. This may be interpreted as a 
tendency towards the formation of chlamydospores, but there is 
no condensation of protoplasm, or investiture with a special 
membrane. lJater on this isolated protoplasm is gradually 
altered, separating into somewhat regular ovoid or fusiform 
Fig. 93.—Zygospores of Mucor phycomyces. (Van Tieghem.) 
granules, which have, toa certain extent, the appearance of spores 
in an ascus, but they seem to be incapable of germination. 
