CUTICULAR STRUCTURE OF PSILOPHYTON. 381 
In addition to the sears of the macroscopic emergences, there are certain 
arrangements of the epidermal cells (see Pl. 37. figs. 2 & 3 and text-fig. 5), 
in which a small circular central cell or space is surrounded by elongated 
radiating cells. These much resemble the hair-bases of many higher plants, 
and Psilophyton may therefore have been provided with a few scattered hairs 
in addition to the larger spines. These supposed hair-bases are very much 
smaller than the spine-bases, and there does not appear to be any intermediate 
stage between the two. No hairs have been seen attached to the bases. 
Text-figure 4 shows a stoma close to the base of a spine, but there is no 
definite or regular association of stomata and emergences. 
Fie. 5. 
[5 
P. princeps. Hair-base (P). From a slide in the Stockholm Museum. 
Before proceeding to a discussion of the significance of these features of 
‘the enticular anatomy, it may be noted that no satisfactory epidermal 
preparations have so far been obtained from the axes of the fructifications 
( Dawsonites arcuatus of Halle) nor from the smooth-stemmed ** Campbelton ” 
type described as Pstlophyton by Dawson. It may be suggested, as a possi- 
bility to be borne in mind, that some of the smooth-stemmed forms may be a 
different state of preservation, having undergone a certain degree of decorti- 
cation before being fossilised. 
