Spermatheca or receptacle of the sperm in copulation, opening into the female duct.
The gametophyte or prothallial generation is thus extremely reduced, consisting of but little more than the male and female sexual cells - the two sperm-cells in the pollen-tube and the egg-cell (with the synergidae) in the embryo-sac. At the period of fertilization the embryo-sac lies in close proximity tube has penetrated, the separating cell-wall becomes absorbed, and the male or sperm-cells are ejected into the embryosac. Guided by the synergidae one male-cell passes into the oosphere with which it fuses, the two nuclei uniting, while the other fuses with the definitive nucleus, or, as it is also called, the endosperm nucleus.
I would insist the father be nothing but a sperm donor.
Sperm sacs generally occupying a good many segments and with simple interior undivided by a network of trabeculae.
There is no possibility that sperm and ova can escape by these tubes not in company with coelomic fluid.