Lampito mauritii · Part 4

are utilized. The undigested particles along with earth are passed out through the anus, as worm castings or vermicasts . The pharyngeal Anatomy The body wall of the earthworm is very moist, thin, soft, skinny, elastic and consists of the cuticle, epidermis, muscles and coelomic epithelium. The epidermis consists of supporting cells, gland cells, basal cells and sensory cells. A spacious body cavity called the coelom is seen between the alimentary canal and the body wall. The coelom contains the coelomic fluid and serves as a hydrostatic skeleton, in which the coelomocytes are known to play a major role in regeneration, immunity and wound healing. The coelomic fluid of the earthworm is milky and alkaline, which consists of granulocytes or eleocytes, amoebocytes, mucocytes and leucocytes. Digestive System The digestive system of the earthworm consists of the alimentary canal and the ­digestive glands. The alimentary canal runs as a straight tube throughout the length of the body from the mouth to anus (Figure . ). The mouth opens into the buccal cavity which occupies the st and nd segments. The buccal cavity leads into a thick muscular pharynx , which occupies the rd and th segments and is surrounded by the pharyngeal glands. A small narrow tube, oesophagus lies in the th segment and continues into a muscular gizzard in the th segment. The gizzard helps in the grinding of soil particles and decaying leaves. Intestine starts from the th segment and continues till the last segment. The dorsal wall of the intestine is folded into the cavity as the typhlosole . This fold contains blood vessels and increases the absorptive area of the intestine. The inner epithelium consists Figure . Lampito mauritii – Digestive System 3KDU\Q[ 3KDU\QJHDO JODQGV 2HVRSKDJXV ,QWHVWLQH *L]]DUG %XFFDO FDYLW\ 0RXWK   Intestinal Caeca In Metaphire posthuma , the th segment has a pair of short conical out growths called intestinal caecae. It is extended anteriorly up to the nd segment. These are digestive glands and secrete an amylolytic enzyme for the digestion of starch. Intestinal caecae