— 5S — 
sublending about 6 tracheides; medullary cells narrowly elliptical 
when the ray is but one cellin height, arcoles round or nearly so, 10 v. 
in diameter, uniseriate, or varely biseriate for a short distance, usually 
alittle distant, sometimes contiguous, with very small, round or nearly 
round, central pores. 
The species here described is represented by a small yellowish- 
brown prismatic fragment which is shown by the approximately pa- 
rallel position of the wedges to have been a long distance from the 
center of the tree. The pith and cortex are unknown. We have, 
therefore, no data regarding the characters ofthe primary wood, wi- 
thout which the generic identification must remain uncertain, notwi- 
thstanding the generally Araucarinian features of the secondary xylem. 
In this, as in most of the other fragments in the collection, the 
tissue is here and there more or less decomposed through the agency 
of anaerobic bacteria. Bacterioids are to be obseryed in the areas of 
partial decomposition . 
Portions of the wood are, however, very well preserved, even 
to the definition, by a dark brown color, of the cell membranes 
which are flanked by the golden-yellow wall-thickening. No distinct 
trace of annual rings is to be seen, nor is there evidence of resin 
ducts. 
In the generally slightly distant arrangement of the areoles and 
the form of the small pores Dadowxylon nummularium resembles Dado- 
rylon Pedrot Zeill., though differing by the more regular disposition 
of the tracheides as well as by the characters of the medullary rays. 
It is probable that the discovery of the primary wood and pith in our 
tree will bring to light far more important differences that may neces- 
sitate a generic separation of the two types. The wood in hand agrees 
as to the abundance and form of the medullary rays with Dadoxylon 
australe described by Arber (L) from the Newcastle series in New 
South Wales. 
All the Australien woods described from the older Gondwana beds 
have very distinct annual rings, while (that published by Professor 
Arber has multiseriate areoles on very short trancheides. From Dado- 
vylon meridionale the type just described is distinguished by its larger 
and more angular tracheides, the noticeably greater number of the 
(1) Tho Glossopteris Flora, 1905, p. 191, figs. 40-15. 
