303 
the Periderm of Fossil Lycopodiales . 
The contents are fairly evenly distributed through the tissue, and not, 
like the dried-up remains of contents in cork, in greater quantity near the 
phellogen. 
(6) Intercellular Spaces. 
As regards intercellular spaces, the periderm partakes of the nature 
of the outer cortex. This is on the whole a closely set tissue with but few 
intercellular spaces, and a certain number have been found in the periderm 
of all the species except Bothrodendron mundum and Sigillaria spinulosa. 
Text-fig. 15. Intercellular spaces in the periderm. A , Lepidodendron selaginoides. U. C.L. 
Coll., A 012. B, Stigmaria. U. C. L. Coll., D 1. C, Lepidodendron Wunschianum. Will. 
Coll., 452. D, Lepidodendron Hickii. U. C. L. Coll., A 1. E, Sigillaria sp. U. C. L. Coll., 
S37. x 265. 
Examples are shown in Text-fig. 15. In Lepidodendron Wunschianum 
the spaces are rather abundant, and attention was drawn to them by Seward 
and Hill. 1 
It would therefore appear that the periderm was at any rate as perme- 
able to gases as the adjacent cortex. 
Seward and Hill ( 29 ), p. 915, PI. Ill, Fig. 18. 
