On Cryptoxylon Forfarense. 361 
pressure. On an average they are 3, inch in diameter and 
have thin walls, though their mode of preservation often 
causes them to appear as if possessing thick walls, but this 
appearance arises from the presence of a mineral deposit on 
the walls which is frequently stained with carbonaceous 
particles (Fig. 5; x75). 
The cells which form the isolated groups are much smaller 
than the matrix (about zy, inch in diameter), and the 
infilling material is always of a dark brown colour, They 
are surrounded on all sides by the larger cells, and the 
longitudinal length of the group is always greater than its 
transverse diameter, the groups being fusiform in shape. 
Two groups shown in transverse section are given at 
Figs. 6 and 7 (x75), and a longitudinal section is given at 
Fig. 8 (x75). The cells are of the same form as those 
composing the matrix, and differ only in size, though their 
function was probably different. The circumstance that the 
mineral filling the groups of smaller cells is always deeply 
stained, and clearly differentiated from the larger cells of the 
matrix, indicates clearly that their cell-contents were of a 
different substance from that filling the larger cells, and may 
possibly have been of a resinous nature. 
This staining of the infilling material in the groups of 
smaller cells is better seen in Figs. 3 and 4, which are 
magnified 22 times; Fig. 3 being a transverse and Fig. 4 a 
longitudinal section, which latter shows the fusiform shape 
of the groups of smaller cells. 
CryPTOXYLON, Kidston, n. g. 
Stem entirely composed of parenchymatous tissue, of which 
the ground mass consists of lax globular cells, among which 
are placed groups of smaller cells. 
CRYPTOXYLON FoRFARENSE, Kidston, n. sp. 
[Plates VIII, IX.] 
Stem composed of lax hyaline thin-walled parenchymatous 
tissue, in which are embedded fusiform groups of smaller 
parenchymatous tissue with dark coloured contents roughly 
