● `color{violet}("Earthworm")` is a `color{brown}("reddish brown")` terrestrial invertebrate that inhabits the upper layer of the `color{violet}("moist soil.")`

● During day time, they live in `color{brown}("burrows")` made by `color{violet}("boring")` and `color{violet}("swallowing")` the `color{violet}("soil.")`

● In the gardens, they can be traced by their `color{violet}("faecal")` deposits known as `color{brown}("worm castings.")`

● The common Indian `color{violet}("earthworms")` are `color{violet}("𝘗𝘩𝘦𝘳𝘦𝘵𝘪𝘮𝘢")` and `color{violet}("𝘓𝘶𝘮𝘣𝘳𝘪𝘤𝘶𝘴.")`

● `color{violet}("Earthworms")` have long `color{violet}("cylindrical body.")`

● The `color{violet}("body is divided")` into more than hundred `color{brown}("short segments")` which are similar (`color{brown}("metameres")` about 100-120 in number).

● The `color{violet}("dorsal surface")` of the body is marked by a dark median `color{brown}("mid dorsal line")` (dorsal blood vessel) along the `color{violet}("longitudinal axis")` of the body.

● The `color{violet}("ventral surface")` is distinguished by the presence of `color{brown}("genital openings")` (pores).

● Anterior end consists of the mouth and the `color{brown}("prostomium")`, a lobe which serves as a covering for the mouth and as a wedge to force `color{violet}("open cracks")` in the soil into which the `color{violet}("earthworm")` may crawl.

● The `color{violet}("prostomium ")`is sensory in function.

● The first body segment is called the `color{brown}("peristomium (buccal segment)")` which contains the mouth

● In a mature worm, segments 14-16 are covered by a `color{violet}("prominent dark band")` of `color{violet}("glandular tissue")` called
`color{brown}("clitellum.")`

● Thus the body is divisible into three prominent regions – `color{brown}("preclitellar, clitellar")` and `color{brown}("postclitellar segments.")`

● Four pairs of `color{brown}("spermathecal apertures")` are situated on the `color{violet}("ventro-lateral")` sides of the intersegmental grooves, i.e., 5th -9th segments.

● A single `color{brown}("female genital pore")` is present in the `color{violet}("mid-ventral")` line of 14th segment.

● A pair of `color{brown}("male genital pores")` are present on the `color{violet}("ventro-lateral")` sides of the 18th segment.

● Numerous minute pores called `color{brown}("nephridiopores")` open on the surface of the body.

● In each body segment, except the first, last and `color{violet}("clitellum,")` there are rows of `color{brown}("S-shaped setae,")` embedded in the epidermal pits in the middle of each segment.

● `color{violet}("Setae")` can be extended or retracted.

● Their principal role is in `color{violet}("locomotion.")`