THALLOPHYTES 
69 
out a tube that penetrates between the body segments or through the chitinous 
skin of the insect. The mycelium finally kills it, filling the body in its vegeta- 
tive growth. At this stage reproduction begins, the mycelium sending out numer- 
ous short branches, from which eventually sporophores arise, reaching the surface 
of the body and each abstricting a single conidium, which is squirted off much as 
is the sporangium in Pilobolus, the dead body of a fly adhering to a window pane 
often being surrounded by a " halo of spores." 
FIGS. 163-167. Mucor: 163, fertile branches (suspensors) in contact; 164, game- 
tangia (unequal) cut off; 165, 166, formation of zygospore by two very unequal sus- 
pensors ; 167, zygospore producing a mycelium, which has already produced a sporangium 
(after BREFELD). 
Conclusions. The Phycomycetes strongly suggest relationship with 
the green algae, their coenocytic bodies resembling those of the Si- 
phonales. They also show a transition from an aquatic (Oomycetes) 
to an aerial (Zygomycetes) habit, accompanied by a transition from 
zoospores to aerial spores. There is also an apparent reduction of the 
