171 
and Affinities of Nematopliycus Logani. 
Laminaria the exogenous increase is from below upwards, accord- 
ing to the growth of the roots, while in Lessonia the growth is 
from above downwards, in proportion to the increase of the leaves.* 
A reference now to Dr. Dawson’s specific diagnosis will show 
that in every particular save one it is erroneous. The fossil does 
not possess a woody trunk, and it is not penetrated by medullary 
rays. The cells are not pleurenchymatous, and there is no double 
series of spiral fibres. There are no disks or bordered pores. One 
character only remains, that the trunks have concentric rings of 
growth ; but this is again and again erroneously employed to esta- 
blish the exogenous, that is, the phcenogamous position of the 
fossil. 
It is difficult to conceive how such a series of errors first took 
possession of Dr. Dawson’s mind, and it is still more difficult to 
realize how that, after the errors were pointed out, first in his own 
preparations and then in a private and friendly letter, they were 
persisted in by a searcher after truth. The characters, which are 
apparent at the first examination of a prepared section of Nemato- 
jphycus, which are obvious at a glance in Mr. Blair’s drawing, and 
which can be to some extent seen even in Dr. Dawson’s faulty 
drawings, especially in the transverse sections, are sufficient to con- 
vince any one who has an intelligent acquaintance with the elements 
of histological botany. It is certain that from this botanical point 
of Anew I have no ground in common with Dr. Dawson. Had it 
been so, there never would have been occasion for this communi- 
cation. 
I have said that Nematopliycus is an anomalous Alga, and, 
indeed, that with the materials known it is not possible to correlate 
it with certainty with any known group of Algae. Since I first 
directed my attention to this remarkable fossil, I have lost no 
opportunity of submitting the preparations to botanists who were 
acquainted with histology, and especially those who had devoted 
their attention to Algae. It is superfluous to say that I have never 
met with one who for a moment imagined the fossil could be coni- 
ferous. On the contrary, the universal testimony has been that it 
is an Alga. 
Archer, of Dublin, thus describes the fossil in his Beports of 
the Proceedings of the Dublin Microscopical Club : — “ There was 
no appearance of ‘disks’; both longitudinal and vertical sections 
seemed to indicate that the mass was composed of a number of 
tubes running in a nearly parallel direction, rarely bifurcating, and 
seemingly not septate or tapering, and with an intercellular me- 
dium, apparently formed of minor tubes The appearance of 
medullary rays was probably produced by accidental cracks or 
fissures, no structure corresponding to them being shown under the 
* See Berkeley’s ‘ Introduction to Cryptogamic Botany,’ p. 57. 
VOL. VIII. O 
