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 earthworm has a closed circulatory system that uses vessels to send blood through its body. There are five aortic arches throughout his body that serve as pumps. The dorsal vessels take blood from the back of his body to the front, and the ventral vessels take blood the other direction, from front to back.n earthworm has a closed circulatory system that uses vessels to send blood through its body. There are five aortic arches throughout his body that serve as pumps. The dorsal vessels take blood from the back of his body to the front, and the ventral vessels take blood the other direction, from front to back.