252 
PROFESSOR W. C. WILLIAMSON ON THE ORGANIZATION 
other hand, consists of cells of various lengths, which are obviously modifications 
of sclerenchyma. These cells meander throughout the greater part of the thickness of 
the endotesta in various directions, and the apparent length of the cells, itself a variable 
quantity, differs according to the direction in which the section has passed through 
them. But at the innermost portion (fig. Ill, b') of this structure all these cells are 
prosenchymatous, and run parallel with the long axis of the seed. Dr. Hooker found 
many of these innermost cells to be barred or spiral ones. Traces of the same struc- 
ture appear in my sections. 
In the transverse section (fig. 112) the cells ( b ') of the innermost layer of the endo- 
testa are seen to be divided by the section transversely to their longer axes. On the 
other hand, immediately external to this layer, we find them, as at b", meandering 
horizontally round the seed. The transverse sections of these latter interlacing cells 
are also seen in fig. Ill, b". The outermost ones in fig. 112 exhibit a strong tendency 
to be prolonged horizontally and radially as at b , where their extremities are in contact 
with the parenchymatous cells of the sarcotesta ( a ). It is evident that these cells are 
more elongated in my sections than in those figured by Dr. Hooker and Mr. Binney*. 
In most of the sandstone casts like fig. 94, the base of the seed exhibits a small defined 
ring, occupying the position of the chalaza, in the centre of which is a little point, at 
which I may presume that a vascular bundle reached the chalaza. My sections, 
however, exhibit no trace of vascular elements. Fig. 110 represents a transverse section 
made through the sarcotesta of the specimen figs. 100-108, enlarged 25 diameters. It 
consists merely of parenchyma with a central aperture, through which, doubtless, the 
vascular bundle of the chalaza formerly entered the seed. The corresponding part of 
the endotesta was damaged in making the section of it; hence I cannot identify the 
upward prolongation of this aperture; but fig. 109 exhibits the aspect of some of the 
neighbouring sclerenchymatous cells of this region enlarged 108 diameters. 
The only region requiring further elucidation is the peculiar structure which appears 
to represent the lagenostome. In their figures Dr. Hooker and Mr. Binney represent 
a small thickening, corresponding with c in my figures 96, 97, and 98, but no reference 
is made to this peculiarity in the text of their memoir. Figs. 113, 114, and 115 
severally represent these structures, enlarged 15 diameters. In each of these instances 
the membrane f is seen to split into the two layers f & f. In f I can trace no 
structure ; but the inner layer (f ) is obviously a thin prosenchymatous tissue, as is so 
usually the case with these nucular membranes. This peculiar organ so evidently exists 
in all the specimens of these seeds that its presence cannot be regarded as merely 
accidental ; whilst its position, and the peculiarity of the membrane out of which it is 
formed, alike indicate its apparent homology with the organ which I have designated 
the lagenostome. Fig. 113 appears to indicate that the nucleus terminated at the base 
of this organ, and did not enter into its inner cavity. 
I am indebted to Johx Aitkex, Esq., of Bacup, in Lancashire, for the loan of the 
* Loc. cit. plate iv. figs. 13 & 15. 
