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.
Earthworms are tubular animals with specific bodily organs taking care of different life functions. Within their tubular bodies are a digestive system, a circulatory system complete with multiple heart-like organs, a simple nervous system and a reproductive system.