in Myzodendron punctulahim, Banks et Sol. 193 
the vascular bundle at the base of the flower, and the 
embryo-sac at its apex is relatively great, and, if the ovule is 
to become a seed, must be bridged over, as is done by the 
placental embryo-sac tube. This tube is essentially nutritive 
and acts as a carrier of food from the floral vascular bundle 
to the developing seed. By treating a longitudinal section of 
the placenta of a semi-mature fruit with Fehling’s solution, the 
embryo-sac tube is found to contain abundant sugar, the 
presence of which and of so many nuclei in the tube tend to 
show that the embryo-sac prolongation has a metabolic as 
well as a translocating nutritive function. Only the one seed, 
the placental embryo-sac tube of which is fully formed, 
develops further. The other two, if formed at all, die at a 
very early stage, mainly owing to a process which is as much 
like strangulation as one can imagine imitated in the vegetable 
kingdom. The space at the disposal of the ovules in the 
ovary is very little, still less when the ovules become en- 
larging seeds, and is removed completely, contributing to the 
death of the other two possible seeds, by the luxuriant growth 
and horizontal elongation of the sterile cells of the seed 
destined to maturity. There is nothing in the structure of 
the placenta to prevent its penetration by two embryo-sacs to 
the base of the flower. In this case the two seeds, supposing 
fertilisation in the two to be simultaneous and other things to 
be equal, may so grow as to kill one another by mutual 
pressure due to the luxuriant sterile cells of the two. In 
the ordinary cases one seed sets up the connection with 
the base of the flower first, and thus gets the advantage 
(Fig. 14 b). 
Returning to this seed’s history it will be noticed that (Fig. 
15) the true apex of the embryo-sac is still covered by the 
single layer of nucellus-cells. This atrophying layer is, very 
soon after this stage, ruptured by the growing seed to which 
the endosperm-cells are being steadily added at the same time 
that the embryo is enlarging under the influence of the feeding 
placental tube. In this way the seed proper comes to lie out- 
side and below the nucellus ; the embryo-sac is not ruptured, 
