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Setae : $\begin{array}{lll}\text{ ventral Lumbricine }& \text{ Perichaetine }& \\ \text{ setae }& \text{ arrangement }& \text{ arrangement }\end{array}$ - Each segment of body wall except first, last and clitellum bears an equatorial annular (perichaetine arrangement) of about 80-120 minute S-shaped and yellowish se (Chaetae). - Setae are half embedded in body wall and half projected backwards upon body surface. - They help in locomotion. - Young Pheretima-Setae present on clitellum also. - Nephridiopores : There are 200 to 250 minute pores of integumentary nephrid scattered upon the surface of each segment except the first two ( 3 to the last). - Upon clitellar segments their number is about 2000 to 2500. - Mid - dorsal pores are present in each intersegmental groove after $12^{\text{th }}$ segment. - Dorsal pores are absent in last groove. - Body-fluid-oozes out always from these pores.

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Updated on: Jun 11, 2023