Lampito mauritii · Part 2

along the longitudinal axis of the body. The ventral surface is distinguished by the presence of genital openings. The mouth is found in the centre of the first segment of the body, called the peristomium . Overhanging the mouth is a small flap called the upper lip or prostomium . The last segment has the anus called the pygidium. In mature worms, segments to may be found swollen with a glandular thickening of the skin called the clitellum . This helps in the formation of the cocoon. Due to the presence of clitellum, the body of an earthworm is divided into pre clitellar region ( st – th segments), clitellar region ( th – th segments) and the post – clitellar region (after the th segment). In all the segments of the body except the first, last and clitellum, there is a ring of chitinous body setae. This body setae arises from a setigerous sac of the skin and it is curved as S – shaped. Setae can be protruded or retracted and their principal role is in locomotion. The external apertures are the mouth, anus, dorsal pores, spermathecal openings, genital openings and nephridiopores. The dorsal pores are present from the th segment onwards. The coelomic fluid communicates to the exterior through these pores and keeps the body surface moist and free from harmful microorganisms. Spermathecal openings are three pairs of small ventrolateral apertures /LWWHU (SLJHLFV SK\WRSKDJXV 'XQJ $QHFLFV JHRSK\WRSKDJXV (QGRJHLFV JHRSKDJXV Figure . Earthworm classification based on ecological strategies Morphology Lampito mauritii is commonly found in Tamil Nadu. It has a long and cylindrical narrow body which is bilaterally symmetrical. L. mauritii is to mm in length with a diameter of . – mm, and is light brown XI Std Biology-Zoology Chapter- lying intersegmentally between the grooves of the segments / , / and / . A pair of female genital apertures lie on the ventral side in the th segment and a pair of male genital apertures are situated latero-ventrally in the th segment.