Describe the internal parts of the Earth worm.

1.	Describe the internal parts of the Earth worm.
Answer» Morphology \tEarthworms have long cylindrical body divided into 100-120 similar short segments known as metameres .\tThe dorsal surface of the body is marked by a dark median mid dorsal line along the longitudinal axis of the body and the ventral surface is distinguished by the presence of genital openings.\tAnterior end consists of the mouth and the prostomium, covering the mouth.\tThe first body segment is called the peristomium, which contains the mouth.\tIn a mature worm, segments 14-16 are covered by a prominent dark band of glandular tissue called clitellum, thus dividing the body into preclitellar, clitellar and postclitellar segments.\tFour pairs of spermathecal apertures and a pair of male genital pores are situated on the 5th -9th segments and 18th segment, respectively.\tA single female genital pore is present in the mid-ventral line of 14th segment.\tNumerous minute pores called nephridiopores open on the surface of the body.\tExcept the first, last and clitellum, there are rows of S-shaped setae in each segment, help in locomotion.

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