animal. This is part of the reproductive system and produces egg capsules. The posterior is most commonly cylindrical like the rest of the body, but depending on the species, it may also be quadrangular, octagonal, trapezoidal, or flattened. The last segment is called the periproct; the earthworm's anus, a short vertical slit, is found on this segment.

The exterior of an individual segment is a thin cuticle over the