1914-15.] Fossil Micro-organisms. 117 
scribes somewhat the same kind of swellings in the fossil fungus Peronospora 
antiquarius, also from the Lower Coal Measures. Weiss states that such 
pear-shaped bodies are of very common occurrence in the outer cortical layers 
of recent mycorhizal structures. The function of these swellings is still a 
matter of conjecture in the case of modern fungi, so we may well hesitate 
to express an opinion with regard to the same structures in fossil fungi. 
At the same time, the analogy with similar swellings in modern bacteria 
is sufficiently striking. In the latter case the connection of the swellings 
with degeneration of the individuals showing them is a matter of common 
knowledge, and this appears to me to be the probable explanation of the 
intercalary dilatations which we find here. The terminal ones, as is described 
in the following sections, are indubitably connected with reproduction. 
The Sporangia . — A terminal dilatation is found at the ends of many of 
the hyphae. These are shown in various stages of development in figs. 8, 
9, and 10, p. 118, and in Plate I, fig. 3. Probably a transverse wall cut off 
the developing sporangium, but I have not been able to find any traces of 
its presence. When fully developed the sporangium was roughly spherical, 
and measured on the average about 24 /x mm.). Its structure is well 
shown in fig. 3 on Plate I. The sporangium-membrane is moderately thin, 
and its outer surface was probably sculptured to form a regular pattern, in 
which the chief feature was the possession of comparatively large regularly 
arranged circular depressions. It is impossible to be certain on this point, 
as the deposit of iron on the surface of these structures prevents accurate 
observation. There is no columella similar to that of modern Mucors, 
though the hypha expands a little outwards at the point where it joins 
the sporangium. In a large number of cases the sporangia are borne on 
relatively long stalks. The discovery of spores inside these structures indi- 
cates clearly their function as reproductive bodies. The deposition of iron on 
their surface shows that if the theory advanced in a later section, that this 
organism had a chemiotactic affinity for iron, be true, the deposition must 
have taken place under water during the lifetime of the fungus and not subse- 
quently after fossilisation by replacement of the lime by iron compounds. 
The Spores . — Most of the sporangia were too thickly encrusted with 
iron to permit of a close observation of their contents. In many cases 
there appeared to be rounded bodies suggesting spores. The immersion 
lens, however, quickly exposed these false appearances. After much 
search I was able to observe one sporangium which had been partly 
cracked and crushed by the process of preparing the slide. Inside this 
particular sporangium, and partly projecting out of the broken part, a 
large spore was distinctly seen. This is shown in Plate I, fig. 4 {a). The 
