154 
tissue into radiating wedges; and in another there were 
traces of a transition from the barred or scalariform struc- 
ture of the vessels seen in Mr. Bmney’s Catamites, to the 
reticulated one of the author’s specimens. All Mr. Butter- 
worth’s sections afforded distinct evidence of the existence of 
medullary rays, even when the vascular tissue consisted of 
barred vessels ; but the latter examples do not exhibit the 
large verticils of medullary radii characterising the author’s 
genus Calamopitus. Mr. Butterworth’s cabinet had further 
furnished the author with the cone of Calamopitus, which 
proves to be much larger than Mr. Binney’s cones of Cala- 
modendron, as well as to exhibit numerous other distinctive 
features. The author proposes to make this cone the sub- 
ject of another memoir. It is a true Cryptogamic spore- 
bearing organ, the spores of which resemble the tetra-spores 
of the Bliodospermous Fucoids in being lodged each in a 
separate cell. They exhibit no traces of Equisetiform 
elaters. 
The additional evidence thus obtained convinces the 
author that in its structure and growth the stem of the 
Calamite has been exogenous, but the structure of the cone 
proves that the plant lias not been, as Mr. Adolphe Brong- 
mart supposes, a Gymnospermous exogen. It has combined 
the woody cylinder of an Exogen with the fructification of 
an Acrogen, a combination that has no existence amongst 
living plants, thus establishing a transition, through the 
modified Coniferee of the coal measures known as Dadoxylons, 
from the Cryptogamic to the Phanerogamic forms of vege- 
tation, meriting the attention of Mr. Darwin. The author 
pointed out that the Dadoxylons themselves were not true 
Coniferee of the modem type, since none of their stems 
exhibited the true glandular pleurenchyma characteristic of 
that type. He also reviewed the attempts made to “restore” 
the Calamite, objecting to them as premature and, conse- 
quently,, unsuccessful ; and, further, gave reasons for 
