141 
1917-18.] Phycomycetous Fungi. 
If this interpretation be correct, we should have in the fifth cell a colony of 
rods that would be indistinguishable in all essential respects from a colony of 
bacteria in a state of active multiplication, and yet one that in this case could 
be proved to have had its origin in a fungus of a Phycomycetous type. 
There can be little question that pleomorphic changes of this kind are far 
more common among modern fungi and bacteria than is generally supposed. 
The formation of very fine filaments has been observed in modern 
fungi. For example, Duncan (2) records the development of very fine 
hyphse in the growth of a species of Achlya, which is saprophytic in the 
dense sclerenchyma of certain Corals (the Madreporias). In this species 
however, the filaments are very short and appear in clusters, each cluster 
emanating from a single point on the hypha. In the fossil fungus under 
description the filaments are in no way distinguishable, except in the 
matter of thickness, from the ordinary branches, and, like the latter, bore 
reproductive vesicles, as is shown below. 
The hyphse showed no trace of transverse septa, except in the special 
case which is detailed below. 
i 
Probable Organs of Reproduction, 
i 
Vesicles in Attachment to the Hyjohce. 
Attached to the hyphse, each by a short branch, are small vesicles, 
examples of which are shown in Plate, fig. 8, and in text-fig. 7. The latter 
figure is a drawing of the same vesicle as is shown photographed in Plate, 
fig. 8. The hypha in these illustrations measures 2 /* in thickness, and the 
vesicle 9/* in diameter. In the finer hyphse vesicles of this type are not 
uncommon, their average diameter being 9/* to 14/*. Exceptionally, some 
are as small as 6/* in diameter, and the largest that was observed measured 
18/*. There is thus considerable variation in the dimensions of the vesicles, 
as well as of the hyphse, in this organism. Each vesicle is a round empty 
structure with a well-defined outer shell. Whilst the shell of most of the 
vesicles is intact, in some ( e.g . text-fig. 7) this covering has a large hole 
in it, which normally is larger than the radius of the vesicle. The vesicles 
may reasonably be regarded as the remains of sporangia of the type that 
is common in modern Phycomycetes, to which group the fossil must be 
assigned. It was not possible to ascertain whether the vesicles were 
separated from the connecting hyphse by means of transverse septa. 
Bodies of the Nature of Oidium Cells. 
It has already been stated that in places the thickness of the hyphse 
changes with abrupt suddenness. When a diminution of thickness had 
