250 
PROFESSOR W. C. WILLIAMSON ON THE ORGANIZATION 
Fig. 95 is the outermost or most tangential of the consecutive series of five vertical 
sections, selected from the nine of which I have already spoken as being made’ from one 
of Mr. Nield’s specimens. There is a small portion of the outermost investment, or 
sarcotesta, seen at «, within which is the denser endotesta at b : the minute structure of 
each of these layers will be referred to presently. The oval outline V merely repre- 
sents the complete contour of the inner surface of this endotesta, where it is in contact 
with the white calcareous spar with which the internal cavities of these seeds are usually 
filled ; f is the nucular membrane, which doubtless was originally in immediate contact 
with the interior of the endotesta, but which has shrunk away from it ; whilst g is a yet 
more internal membrane, apparently identical with the perispermic one of the previously 
described seeds. 
Figs. 96 & 97 are two sections made near to the central axis of the seed, so that the 
long narrow micropyle ( d ) comes into view in both ; we also see in each of them the 
appendage ( c ), on the apical extremity of the nucular membrane (f). In each section 
the inner or perispermic membrane ( g ) has become shrivelled and collapsed. Fig. 98 is 
a tangential section, which has just avoided passing through the micropyle, and in 
which the lagenostome (c) is still observable ; whilst in fig. 99 we return nearly to 
the conditions seen in fig. 95, but on the opposite side of the seed. The perispermic 
membrane does not appear in this latter section, as would have been the case with a 
similar tangential one, made through the right-hand side of either of the figures 97 & 98. 
Figures 100 to 108 represent an instructive selection of the most characteristic of my 
eighteen transverse sections, made from one of Mr. Butterworth’s specimens. Fig. 100 
has intersected the seed near the base of the micropyle, the section of the open trian- 
gular tube of which is seen at d. The testa is here very thick in proportion to the 
diameter of the central canal which it encloses. At each of the angles of the latter the 
endotesta projects outwards with the sharp angle seen at V b', the third one having been 
accidentally broken away. On either side of each of these three projections of the 
endotesta is another smaller prominent acute angle ( b " b"), whilst midway between each 
of the three primary angles ( b b') the endotesta exhibits a third rounded prominence 
(b''',b"'). We thus see that the hard endotesta, deprived of its soft sarcotesta (a), had 
twelve prominent longitudinal ridges, nine of which had sharp keel-like margins, and 
the remaining three were more rounded and swelling*. Though the external outline 
of the sarcotesta (a) is less sharply defined than that of the endotesta, we yet see that 
to a considerable extent the former follows the latter, the differences seen in the sections 
being due to shrinkage from some collapse in the soft parenchymatous cells of the outer- 
most layer. 
In fig. 101 the section is made a little below the base of the micropyle, and I doubt not 
that in the recent seed it would have passed through the upper extremity of the nucleus ; 
* Yiewed in the light now thrown upon these structures in Trigonocarpon, it seems to me possible that 
some of Professor Newberry’s species of Rluibdocarpus (Joe. cit. pi. 44) may merely he the endotesta of seeds 
of that genus deprived of their sarcotesta. 
