The spinal cord begins at the occipital bone and extends down to the space between the first and second lumbar vertebrae; it does not extend the entire length of the vertebral column.
Earthworms are invertebrates, lacking a skeleton. To support and shape the body, they are filled with coelomic fluid. Earthworms sometimes appear to have a belt or saddle around their bodies; this is a clitelum, a structure containing maturing eggs.
Reproductive System. An earthworms needs to mate with another worm to produce eggs, but they don't have to look for a specific gender. Most earthworms are hermaphrodites, which means they carry both male and female reproductive organs. To mate, the earthworms basically exchange sperm.