TRANSACTIONS OF SECTION K. 685 
years before felling, but the last year showed at the tip an increase in the radial 
increment and in the autumn wood percentage, suggesting a partial recovery. 
Other points noted in the research :— 
1. Pathological formation of zones of contiguous resin ducts, especially at the 
boundary between two annual rings. 
2. Partial rings may be produced, even over very small areas of the meri- 
stematic sheath, when the cambium is failing in activity. Also the size of the 
radial increment may differ greatly even along two very closely adjoining radii. 
3. The hardness of the timber seems to be independent of the percentage of 
autumn wood in the annual rings.’ 
2. The Geological Evidence with regard to the Relative Age of the 
Abietineze and the Araucarinee. By R. B. THomson, B.A. 
Two forms have been considered important as indicating the great age of the 
Abietine, Pityorylon chasense of the Permiaw and P. conwentzianum of the 
Carboniferous. Both these forms have recently been shown not to be authentic— 
the former structurally and the latter geologically. There is left no Abietinean 
‘form either in or earlier than the Triassic, where the first Araucarian (Wood- 
worthia), according to the theory which regards the Araucarinez as derived from 
the Abietinee, makes its appearance. The conclusion is sufficiently evident, but 
certain features of the forms which are considered transitional to the Araucarineze 
are pertinent. The Triassic form, Woodworthia, has only the spur shoot of the 
Abietinez, being in pitting and ray structure practically Cordaitean or Arau- 
carian. This spur shoot, too, is of a very primitive type—persistent and with 
many leaves. Araucariopitys of the Cretaceous closely resembles a pine—in 
pitting, in ray structure, in resin canals and in its early deciduous spur shoots. 
That the older form should show more Araucarian features and the more recent 
one have the more pine-like structure is the reverse of what the Abietinean theory 
of the ancestry of the Araucarinee demands. The evidence from these tran- 
sitional forms geologically considered is in accord with and supplements that of 
the geological records themselves. 
3. The Zoospores of the Laminariacee and their Germination. 
By J. Luoyp Wittiams. 
In consequence of the announcement by Drew that the so-called zoospores of 
Laminaria are gametes, and that he had observed their fusion, the author re- 
peated the investigation described by him at the Bradford meeting of the British 
Association, employing, in addition to other methods, the culture solution method 
used by Drew. The conclusions originally arrived at were confirmed. As might 
have been inferred from Drew’s own description and figures, the colourless, 
spherical, fusing organisms seen by him were not the Laminarian zoospores, but 
monads. The real pear-shaped zoospores, with their prominent bent chromo- 
plasts, never fuse. When they settle down they become spherical, are invested 
with a wall, and the curved chromoplast divides in two at the bend. A long 
tube grows out at one side of the spherical spore case; into this the two chloro- 
plasts and most of the other contents migrate, the nucleus remaining behind. 
The nucleus now divides, and the two daughter-nuclei move into the tube. An 
enlargement is formed at the distal end, in which are found one of the nuclei, the 
chloroplasts, and most of the other cell contents. A transverse well separates it 
from the tube, in which the second nucleus, together with a trace of cytoplasm, 
may be found; later on this nucleus degenerates and becomes a structureless mass. 
The new cell grows in size, the chloroplasts multiply, and division may take 
place, in which case a single chain of cells or an extensively branched, protone- 
matoid structure may be formed. The protonema may give rise to a Laminarian 
germiing in a fortnight or less, or it may remain in this condition for many 
months. 
* Cp. Hartig, Holzuntersuchungen, S. 6, Berlin, 1901. 
