Earthworm, LM

Earthworm, light micrograph (LM). An earthworm is a tube-shaped, segmented animal that is commonly found living in soil, feeding on live and dead organic matter, the digestive system runs straight through its body. It conducts respiration through its skin, and it has a twin transport system composed of coelomic fluid that moves within the liquid filled coelom and a simple, closed blood circulatory system. It has a central and peripheral nervous system, this consists of a central system of two ganglia above the mouth, one on either side, connected to a nerve chord running back along its length to motor neurons and sensory cells in each segment. Circumfrential and longitudinal muscles on the periphery of each segment enable the worm to move. Similar sets of muscles line the gut and whose actions move the digesting food toward the worms anus. Earthworms are hermaphrodites., Photo by STEVE GSCHMEISSNER/SCIENCE PHOTO LIBRARY