I've got the worm summary written up more or less. I gloss over a lot of detail as it is but this is probably pushing the limit for how long I can talk just to say how things are related to each other.
So worms branched out in a lot of directions early on. The good example for early eyesight is the flatworm.
The eyespots are pretty visible and thanks to those dark spots and the virtue of having two different eyes they can work out the direction light is coming from.
They're an early side branch though. It is the roundworms that are more on the path to the lifeforms that came onto land. Many of these lived in and ate mud. A digging tube is something we obviously know works for a worm body after all.
An interesting side branch produced a body similar to a caterpillar but the velvet worms are basically repeating segments with just a little change for the head.
But something much more attention grabbing arose. Centipedes. These are much more obviously segmented roundish tubes with a special front and back, probably very different organs arrangement in each segment.
Spiders and their relatives, as you should know, come from a different lineage than insects. These basically opted for shorter bodies and relatively longer legs early on.
Now if you remember that video from awhile back I've actually been talking exclusively about the mouth-first creatures.
On the other end of things you've got some more fleshy worms (acorn worms have an interesting shape,) while starfish are an interesting deviation frm the left/right tube shape and sea squirts contort the organs around so the anus and mouth point out of their top sides. The cephalopods also split off here to produce everything from clams to squid.
The wormiest creatures here are annelids which lead to the actual worms we're flat out the most familiar with. Polychaetes though, are the ones I want to bring up- they have shelly segments with very obvious paddles sticking off of the sides.
Also there's bryozoa which live in a tube and grab tiny foodstuffs with a fan structure.
The lineage that I'm really getting at is the one that developed a specific spinal chord-
ok, they didn't have spines yet so it wasn't a spinal chord but it leads into it.
elsewhere nerves were mostly decentralized and just formed a net and if anything there was a ring somewhere around the mouth. Some of these have cartilage types of skeletons but the bones that are so prominent in fish, reptiles, mammals, and birds show up after this, first as the vertebrae that go around the spinal chord, though this is a progression of the cranium that was an earlier protection for the widest portion of the spinal chord.