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.
An earthworms has 100 to 150 body segments, each having muscles and bristles. An earthworm's setae are so tiny, they're almost invisible. He uses them to anchor himself while navigating in soil, or when a bird is trying to pull him from the ground. The earthworm stretches out and holds onto the earth with his front bristles. He then contracts his body forward.