anata 
AND ON POLYEMBRYONY IN THE HIGHER PLANTS. 29 
of the embryo-sac, which is densely filled with solid substance, 
so that the entire embryo-sac is rendered perfectly opake by it. 
It is remarkable that the young embryo remains in this case for 
so long a time undeveloped; as soon as the end of May I saw 
it in the form of a simple globular vesicle, and in this state it 
remains for nearly a month, as represented at fig. 2. Pl. II. In 
this case the young embryo was already so much surrounded 
by albumen, that it was difficult to recognize it therein. With 
the commencement of July the embryo-sac expands very much 
indeed; the swelling also extends from the embryo, and de- 
scends deeper and deeper, so that very frequently in the first 
week of July it forms a nearly perfect ellipsoid figure; and at 
the Jower extremity only, the chalaza-end, it is still provided 
with a small stipes, by which it remains attached for the whole 
time: it is not until after the embryo-sac, with the albuminous 
body, has nearly attained its perfect development, that the fur- 
ther development of the embryo begins. 
The small size which the embryo has acquired in the middle 
of July is shown at fig. 4. Pl. II., from a drawing magnified 
twenty times of a longitudinal section of the fruit: h represents 
the embryo-sac with its short stalk; 7 and & the small embryo 
which is just about to expand, but still exhibits no trace of coty- 
ledons. From this time the enlargement of the embryo proceeds 
rapidly, and as it elongates it breaks through all the transverse 
septa of the large cells of the embryo-sac, and is then situated 
exactly in the longitudinal axis of the albuminous body. Fig. 6. 
PI.II. gives a representation of the embryo observed in the middle 
of August, likewise magnified twenty times. Figs. 4 and 5 serve 
to explain the structure of the fruit ; on the cross section in fig. 5, 
aa exhibits the external portion of the calyx; this is the thick 
outer envelope of the berry, which in the ripe state acquires the 
white parchment- like condition, at last becomes thinner, and con- 
tains the spiral-tube-bundles which give off separate bundles to 
the sepals: & 6 shows the inner portion of the calyx, the cells of 
which are elongated during the development of the berry in a 
horizontal direction, so that from this cause the fruit expands 
horizontally or in breadth, and at last becomes quite globular. 
Simultaneously with this excessive elongation of the cells, there 
occurs a metamorphosis of the previously hardened cellular 
membrane into a gelatinous substance, which probably is no- 
thing else than the viscin, which is contained in such quantity 
