46 Salisbury. — On the Structure and Relationships of 
of them in the same direction, so that their course is at a very narrow angle 
with the horizontal plane, and in transverse sections they appear cut 
obliquely or almost longitudinally for some distance. Where the members 
of a band are in one layer they appear to all bend in a similar manner, but 
where the band is more than one element in thickness those of each layer 
probably bend in opposing directions, but it cannot be definitely ascertained 
whether or no they again take up a longitudinal direction. 
The extreme irregularity of the 
course of the fibres is shown by the 
inconstant numerical relation between 
those cut obliquely and transversely, 
and, to still further complicate the struc- 
ture, the bands do not always remain 
in the same vertical plane. 
Owing to this complex interlacing 
of the outer elements of the sclerotesta, 
it presents a plait-like appearance when 
cut by sections tangential to the surface, 
as is seen in PL IV, Fig. 3. 
Eventually the thickened elements 
of the sclerotesta pass obliquely out- 
wards by a well-marked transition into 
the sarcotesta. 
In the outer part of the sclerotesta, 
and there only, elongated secretory elements partially or entirely immersed 
in the sclerotic tissue are present, which pass out into the sarcotesta at one 
point and occasionally into the sclerotesta again at another (PL IV, Fig. 6, 
rn.sl). In all respects these secretory elements resemble those present in 
the sarcotesta. 
For convenience of description the sclerotesta has been treated as con- 
sisting of two parts, the plane at which the different structure is assumed 
being variable. There is, in fact, little doubt that the outer zone represents 
the terminations of a large portion and perhaps even all of the longitudi- 
nally directed fibres, and cannot possibly be regarded as the region of 
fusion of two morphological surfaces, as has been suggested for the stony 
layer of the Cycadean ovule. 1 
Text-fig. 5. A portion of the sclero- 
testa as seen in transverse section, showing 
the vertically directed fibres at the interior 
and the almost horizontal direction at the 
periphery ; a single secretory sac is also 
present. 
2. The Sarcotesta. 
(a) General Structure. The sarcotesta in the living state must have 
been the most pronounced feature of this seed, for even as petrified it 
invests the sclerotic shell in the middle region to a thickness of over 4 mm. 
1 Stopes : The Double Nature of the Cycadean Integument. Ann. Bot., vol. xix, 1905. 
