228 PROFESSOR ALEXANDER DICKSON ON THE EMBRYOGENY OF 
with the comparative density and opacity of the apex of the germ and of the 
body at the bend, in both of which situations cell-multiplication is actively going 
on. The apex or head of the germ now exhibits a slight rounded enlargement 
(emb), the rudiment of the embryo proper; the elongated neck represents the 
suspensor (susp); while the active cell-multiplication, giving opacity to the 
region of the knee-like bend, is the first mdication of the formation of the extra- 
seminal root-process. I have given an enlarged outline figure of the germ at this 
stage in Plate XV. fig. 14. 
In Plate XIV. fig. 6, the germ is a little further advanced. Its curvature is 
more strongly marked, the elongated and pointed base standing nearly at right 
angles to the suspensor. The terminal enlargement or embryonal globule (emb) 
is now very distinctly indicated as a globular head. A slight bulging or rounded 
projection of the outer aspect of the body of the germ at the knee-like bend is 
now to be seen (esr), the rudiment of the extra-seminal root-process. In Plate 
XV. fig. 15, I have given a much enlarged figure of the germ at a stage some- 
what intermediate between the two last described, showing the cellular structure. 
The elongation and enlargement of the pointed base by dilatation of its con- 
stituent cells are very marked, as also is the elongation of the suspensor by a ~ 
somewhat similar though not so excessive cell-dilatation. ‘The regions where 
cell-multiplication is going on actively, viz., the “ embryonal globule,” and the 
body of the germ at the knee-like bend, are conspicuous by the comparatively 
small size of the cells. 
In Plate XIV. fig. 7, a section of a fruit-lobe at a somewhat later stage is 
represented. The bulging on the outside of the knee-like bend is now developed 
into a short, thick, cylindrical process—the young extra-seminal root (es). This 
has bored its way almost horizontally outwards through the seed-coats, at a 
poimt considerably distant from the micropyle, the space corresponding to the 
elongated base of the germ intervening between them. It is further to be noted, 
that this extra-seminal root-process has begun to force its way into the 
substance of the carpel (c) immediately on making its exit from the seed-coats. 
In Plate XV. fig. 17, an enlarged figure of the germ from this section is given, 
showing the cellular structure. The elongated base and extra-seminal process 
are seen in section ; the suspensor and embryonal globule in surface view. The 
enlargement of the cells of the elongated base and of the suspensor is very dis- 
tinct. The extra-seminal process exhibits very nearly the same characteristics 
(except in consisting of a much greater number of cells) as that of 7. majus at 
a corresponding stage. Its rounded extremity is formed by a layer of more or 
less columnar cells of considerably greater length than those immediately behind 
them. The subsequent growth of this process is due in great measure to elon- 
gation of its constituent cells; but if cell-multiplication does go on during the 
elongation, it must, { think, be intercalary and not apical. 


