Penhallow. — Nematophyton Ortoni , n. sp . 43 
ture to special locations, a new series of sections was prepared 
at the Peter Red path Museum. It was found upon examina- 
tion that there were no material differences of structure 
exhibited by the two sets, so that no special reference to 
them is required. The structure was found to be most 
beautifully preserved, and in this respect it is comparable 
with the Gaspe specimens of N. Logani. 
In transverse section the structure is seen to consist of 
numerous round, thick-walled, and rather widely separated 
cells of rather uniform size, the larger having a diameter of 
about 67 \x. Between these cells others are to be seen 
running more or less transversely at various angles, and there- 
fore interlacing with the first or longitudinal series. The 
spaces between the cells are occupied by small crystals of 
silica and a limited amount of carbonaceous matter, which 
shows no disposition indicative of structure. So far very 
searching examinations have failed to disclose anything of 
the nature of smaller hyphae such as distinguish the structure 
of N . Logani , N. eras sum, and N. laxum , and it is impossible 
to say if such were at any time present, though the presence 
of carbonaceous matter among the siliceous crystals would 
seem to suggest the possibility of hyphae, or at least of some 
structure, having been present, since it has already been shown 
in the case of N. Logani and N. crassum , that the carbona- 
ceous matter of the original structure often becomes distributed 
in such ways through the influence of crystallization l . 
There is no evidence whatever of radial spaces such as 
were found in N. Logani. But there are rather numerous 
isodiametric areas, about 0-30 mm. broad, occupied entirely 
(Fig. 3) by masses of very narrow and densely interlacing 
hyphae, having a diameter of 4-8 \x. In the sections so far 
submitted to examination, the structure of these hyphae has, 
in most cases, been destroyed by crystallization, and in the 
few instances where the structure was intact it was not possible 
to ascertain if they were septate, though the occurrence of 
1 M. Micr. Jill. X. 69, 70. Trans. R. Soc. Can. VII. iv. 23; Proc. U. S. Nat. 
Mus. XVI. 1 15. 
