Annelids are worms with rings, such as earthworms.
Use a magnifying lens to examine the surface of an earthworm. Notice the individual segments. Adult night crawlers have up to 170 segments while red wigglers have about 95. On the first segment is the mouth and on the last segment is the anus.
In the video, you can see the individual segments with a bunch of small hairs or bristles called setae. The setae help the earthworm move. There are four pairs of setae on each ring or segment.
Question:
If an earthworm is cut in half, will both parts live?
Answer:
The rear half of the worm will die, but the front half may live and replace the lost half of its body. This is called regeneration. The head end must be long enough to contain the clitellum and at least 10 segments on the posterior (tail-end) side of clitellum. This makes up about half the length of the worm. The new posterior segments will be slightly smaller in diameter than the original segments and sometimes a bit lighter in color.
For more information about earthworms see,
EARTHWORM INDEX