356 Barber . — Cupressinoxylon vec tense. 
The first (p. 357) table gives the number of medullary rays 
per sq. mm., as well as their heights in cells. All the slides 
here examined were tangential. The method adopted was 
to count the number of medullary rays in the field of the 
microscope, the area of the field having first been accurately 
determined. In the case of medullary rays partly included 
those only were reckoned which were more than half in the 
field. 
The second table (p. 358) gives the number of medullary- 
ray-cells per sq. mm., as well as the average area of each cell. 
These combined give the proportion of medullary-ray-tissue 
to the whole wood. The observations on the radial sections 
are given as control measurements. The areas are calculated 
from the tangential measurements alone. Each medullary- 
ray-cell is practically an ellipse. In measuring its width 
it was impossible to decide how much of the cell wall 
belonged to the cell of the ray and how much to the adjoin- 
ing tracheides. The whole thickness of the wall on one side 
was therefore added to the lumen. 
Pits were observed only on the radial walls of the medullary- 
ray-cells. In both radial and tangential sections these were 
seen to be simple. In shape they were oval and obliquely 
placed, usually two or one per cell, occasionally three, or more 
rarely four. The higher numbers were, as usual, on the outer 
cells, the middle cells having frequently one pit each. This is 
in accordance with the Sequoia type of wood. 
The longest diameter of the medullary-ray-pits could only 
be accurately determined in two sections. In branch (1) it 
varied from 3 to 10 yu, the average of fourteen pits being 6*5 /x. 
In root (2) the diameter varied from 6 to 12/01, the average 
of thirteen pits being 8 /u. 
Intercellular spaces were very clearly seen in the medullary 
rays, their distribution being as in recent woods. 
Resinous Parenchyma. 
There are no resin-ducts. Wood-parenchyma is however 
to be found among the tracheides* and this, from analogy 
