PLANARIA
- There are sexual and asexual planaria. Planaria are hermaphroditic possessing both testicles and ovaries. Each planarian transports its excretion to the other planarian, giving and receiving sperm. Eggs develop inside the body and are shed in capsules. Weeks later, the eggs hatch and grow into adults. Asexual reproduction, the planarian detaches its tail end and each half regrows the lost parts by regeneration, allowing adult stem cells to divide and differentiate, thus resulting in two worms. Some Planaria are exclusively asexual, whereas some can reproduce both sexually and asexually.
BEDFORD'S FLATWORM
- Like all flatworms they are hermaphroditic and have two penises. During mating, they fence with one another using their penises attempting to stab and inject sperm in their opponent, while avoiding being fertilized themselves. They are able to inseminate their opponent by injecting their sperm into any region of the other's body they are able to penetrate. After successfully injecting the other, the sperm streams through their partner's body on their way to ovaries, where they will fertilize the eggs. The stream is visible through the body tissue of the worm, appearing as pale streaks like lightning jags
NEW ZEALAND FLATWORM
- Reproduction involves the production of egg capsules of about 8 mm in length. The capsules are shiny, flexible and cherry red in color at first and later darken to black after several days. After an unknown incubation period, several pale, tiny flatworms hatch out of the brittle capsule. One egg capsule is produced at a time with the bulge clearly visible in the dorsal of the adult worm.