iio Scott and Mas ten. — The Structure of Trig ono car pus. 
outer cells of the sarcotesta in Cycas Beddomii are described ns having 
a water-storing function, and their presence is perhaps to be correlated 
with the dry habitat of this species 1 . No similar cells are found in 
Trigonocarpus . Apart from this difference it will be seen that in the 
details of structure of the testa, Trigonocarpus P arkmsoni exhibits some- 
what close similarity with that of one of the most complicated of modem 
Cycads. 
The Inner Flesh. The next question which may be considered is that 
of the possible existence of a thin-walled tissue within the sclerotesta, and 
corresponding in position with the 4 inner flesh ’ of the seed of a Cycad. 
Such a layer may be called an 4 endotesta,’ but in view of the use of this 
term by Williamson and others for the stony layer or sclerotesta of 
Trigonocarpus , we have thought it better to avoid confusion by using the 
term ‘ inner flesh.’ 
In none of our specimens is such a layer preserved in a recognizable 
condition, excepting just at the base of the body of the seed. In one 
of our slides 2 , a longitudinal section passing in a slightly tangential 
direction through the base of the seed, a tissue consisting of parenchyma- 
tous cells, is seen lying between the nucellus and the sclerotesta. The only 
evidence for the existence of an inner flesh higher up in the body of the 
seed is found in the commonly somewhat irregular and 4 unfinished ’ ap- 
pearance of the inner boundary of the sclerotesta. This 4 unfinished ’ 
appearance is particularly noticeable at the upper part of the body of 
the seed, and the lower part of the micropylar tube. On the whole we 
think the evidence is sufficient to make it probable that Trigonocarpus 
possessed a continuous inner fleshy layer within the sclerotesta. The 
reason why the cells of this layer are not more generally preserved, is 
probably that the cells themselves were of a delicate nature, and also that 
the hard impermeable coat of the seed prevented the infiltration of the 
petrifying material before the tissue had undergone disorganization. 
An inner fleshy layer probably existed in most of the Palaeozoic seeds 
of similar organization to Trigonocarpus , although it is never found even 
in a fair state of preservation. Prof. Oliver has described traces of such a 
tissue in Stephanospermuni caryoides 3 , while in Stephanospermum akenioides 
a delicate network of thin-walled cells is sometimes seen lying in the 
angle between the base of the nucellus and the lining of the sclerotesta 4 , 
just as in some of our slides of Trigonocarpus P arkinsoni. 
The very imperfect preservation of this tissue is unfortunate, in view 
of the great importance of determining its relation to the nucellus within, 
whether the nucellus stood up freely, separated from the testa throughout 
the greater part of its length, i. e. from the pollen-chamber to the chalazal 
1 Stopes (’05), p. 445. 2 Slide 941 S. 
3 Oliver (’04) (i), p. 374. 4 Oliver (’04) (1), p. 367. 
