48 Salisbury. — On the Structure and Relationships of 
and the projections themselves often appear as narrow vertical series 
partially or completely separating adjacent intercellular spaces (PL IV, 
Fig. 10). Although the above fundamentally expresses the arrangement of 
the cells in this region, it was subject to great irregularity. 
In the living condition this tissue must therefore have been remarkably 
light and spongy, and if these seeds were shed into water would render 
them of great buoyancy. Several seeds of this affinity, e. g. Trigonocarpus 
P arkinsoni? P achy testa? and Aethiotesta elliptic a? exhibit a lacunar sarco- 
testa, and the suggestion put forward by Renault for Aethiotesta that this 
served as a mechanism for dispersal by water may well have been true also 
in the present instance, all the more that the method of occurrence of 
fossilized vegetable remains favours the view that 
they were in part components of water-borne 
drift. 
(b) The Peripheral Zone. At the exterior 
the sarcotesta was bounded by a very ill-preserved 
layer of thin-walled cells (1*5 jut-3// tangential 
x 2 [jl radial). Beneath this epidermis there were 
numerous sclerized fibres between which a soft- 
walled parenchymatous tissue was most likely 
present originally, though all except a few 
remnants of walls have become disintegrated. 
The total width of this peripheral zone where 
there is no evidence of crushing or contraction 
is about 0-3 mm. In most cases the sclerized 
elements appear irregularly scattered, probably 
due to post-mortem changes, as in several places, 
where this zone has almost retained what was probably its original width, 
they are seen to be grouped together to form somewhat irregular radial 
plates (PI. V, Fig. 19). Each plate was formed of from % to 6 elements, 
the higher number probably being the more usual, whilst tangentially the 
groups generally form either a single or a double row. 
Not infrequently there were considerable local aggregations tangential 
to the surface, forming broad bands which may well have arisen through 
the lateral fusion of a number of the sclerotic plates. In outline each broad 
band formed a continuous hypodermal layer of sclerotic elements, with 
occasional projections inwards. Owing to crushing and contraction, many of 
the sclerotic bands have come to bccupy an oblique or even tangential direc- 
tion, causing irregularity and superposition of the originally radial plates 
Text-fig. 6. A small portion 
of the outer sarcotesta, showing 
the large intercellular spaces. 
1 Scott and Maslin, loc. cit., p. 101. 
2 Renault : Bassin houiller et permien d’Autun et d’Epinac, vol. iv, p. 390, and PI. LXXXIII, 
Fig. 10. 
3 Renault: M&n. Soc. d. Sci. nat. d. Saone-et-Loire, p. 1, 1887. 
