Platyhelminthes
Platyhelminthes or flatworms are a phylum in the animal kingdom. All organisms in this phylum are invertebrates. They have no specialized circulatory or respiratory systems which causes them to have no body form. The greek word Platyhelminthes literally means "flat worm."
Procotyla fluviatilis
There are no male or female flatworms. They are hermaphrodites, which means when they mate, both flatworms can lay eggs. Several eggs are laid in one cocoon two to four millimeters wide. Eggs hatch in about two weeks, unless it's near Winter. Then the eggs wait until Spring. During penis fencing, each flatworm tries to pierce the skin of the other using one of its penises. The first to succeed becomes the de facto male, delivering its sperm into the other, the de facto female. For the flatworms, this contest is serious business. Mating is a fight because the worm that assumes the female role then must expend considerable energy caring for the developing eggs.
Tapeworms
Tapeworms are also hermaphrodites. They have male and female reproductive organs but still need a mate to reproduce. During reproduction, one tapeworm finds another and they each fertilize each other's eggs. After the eggs are fertilized, they are released and develop outside of the parent.
Leopard Flatworm
Most flatworms can reproduce asexually or sexually. That is the case with the leopard flatworm. Leopard flatworms are also hermaphrodites. Some ways of their reproductive characteristics is the anatomy, hence, and species diagnoses. The males reproductive system is basically based on their coloration, and color pattern. There for, the female P. pardalis is more attracted to the male with the most and biggest spots. The reproduction system works the same way as a tapeworm, for example.