1914-15.] Fossil Micro-organisms. 115 
necessity be the case, for it is obvious that the delicate hyph83 without some 
such stiffening process could not have been preserved. Examples of these 
hyphae are shown in Plate I, fig. 1, and in figs. 1 and 2, p. 116. The hyphal 
nature of these tubes is sustained chiefly by the fact of their attachment to 
sporangia, and by the discovery of remains of spores in these sporangia ; 
but even if these were not present, the appearance of the threads themselves 
gives sufficient support to their hyphal nature. 
The threads form a web-like interweaving mass ; they are uniform in 
thickness and exhibit branching, demonstrating all the essential character- 
istics which we associate with the hyphss of modern fungi. 
That the iron was collected on their bodies during the lifetime of the 
threads is evidenced by the fact that the deposition of iron shows the same 
variations on these threads that we see on the bodies of the threads of 
Leptothrix ochracea — the best known of the iron- bacteria. 
On some threads the deposition of iron had been small, with the result 
that the membrane on both sides is sharply contoured. In others where 
the deposition had been thicker, whilst the general tubular effect w^as 
retained, the edge of the membrane had become irregular and slightly 
broken. In a still more extreme case only a tumbled mass of fragments, 
still retaining, however, the tubular conformation, were to be observed. 
All these stages may be seen in living and in dead threads of the modern 
Leptothrix ochracea, and there seems no reason to doubt that the process 
of deposition was the same then as it is now. 
By examining the hyphse on which the deposition of iron had been 
slight, we are able to obtain some more information concerning them. The 
ends were hemispherical, as seen in fig. 3, p. 116. In all the threads examined 
no trace of transverse walls could be seen. In many cases what appear 
to be transverse walls turned out on closer investigation to be nothing more 
than irregularities in the deposition of the iron. I have examined hundreds 
of hyphae for the presence of transverse walls, and am convinced of their 
absence. Where the deposition of iron had been slight it was possible to 
trace signs of a slightly sinuous tendency, but normally the threads were 
seen as straight fragments. The membrane was thin and delicate, and very 
much the same as that of modern hyphae. At places one saw the hyphae 
‘‘ end on,” and, as expected, the sections were round in outline. Branching 
took place with more or less uniform regularity. It was in this feature 
that this fungus differed strikingly from modern organisms of a similar 
nature. It was not uncommon to find branches which were thicker than 
the parent hyphae which gave rise to them. In many places there was a 
thick strengthening cushion at the point of insertion of a branch, and this 
