He1ga Harder, Age 13, Of Winnipeg, Man., Canada, for her question:
Do earthworms lay eggs?
The earthworm is a biological wonder. He has no eyes, but he reacts to light. He Has no ears, yet he reacts to sound.. He has a system of blood vessels which is kept pumping by five pairs of hearts. His digestive system has a crop and a gizzard. One would expect such an unusual animal to have an unusual method of handing on life, and so he has.
Strictly speaking, we cannot refer to little pinky as him or her, for every Earthworm is both a male and a female. Each worm had two parents, but each parent is both a mother and a father. This makes for a complicated family life, but it does not bother the baby worms at all. The little fel1ows come from eggs that were left to hatch in the ground and they never meet either of their parents. Every earthworm manufactures two types of reproductive cells. They are made in The region between segments nine and 13, counting from the tapered head end of the worm's body. Behind this area, the worm is circled with a puffy ring ca11ed the Clitellum. At certain times, the clitellum oozes forth slimy mucus. A pair of earthworms starts a new family when the ground is moist and the light is Dim. One parent may crawl a long way to meet the other, or the two may live in Neighboring burrows. Each parent transfers a supply of male or sperm ce11s to the other. The c1itellum oozes a flood of slimy mucus to help the microscopic cells to flow between the two worms. Each worm now has a supply of male cells from another worm, plus a supply of female egg cel1s of its own. The slippery clitellum begins to s1ide forward over the worm's body. It gathers sperm cel1s and egg cells, and in a ring of mucus the male and female ce11s meet and fertilize each pair of cells is a worm's egg.
The mucus ring within the clitellum is now an egg sac. It slides forward and soon slips over the worm's head., and its sides seal themselves together. The egg sac or cocoon is no bigger than a grain of wheat. The parent worm leaves it on or in the ground., and after about two weeks the miniature eggs hatch into a swarm of miniature worms.
The worms which hatch from a cocoon have the same mother and the same father. But their father also became a mother and gave birth to a brood of youngsters. The father of this second brood was the mother of the first brood of wormlets. The youngsters measure eight to an inch. They soon escape into the ground and after two years are fully grown and ready to become mothers and fathers.