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.
Skin is the largest organ compose of dermis and epidermis. skin, nail, hair are the part of intergumentary system. Skin is the largest organ compose of dermis and epidermis. The skin is the major organ of the integumentary system. Other parts of the integumentary system in humans include the hair and nails. Integument system is the largest organ of the body. It is derived from Ectoderm of the embryo.