What evedince suggest that arthropods might have envovled from annenlids?

Annelids are segmented in much the same way as arthropods (think of earthworms). Primitive arthropods include centi- and millipedes, with many unspecialized legs (legs in more advanced arthropods often specialized to form antennae, mandibles and pedipalps), and they're as long and thin as segmented worms. Also, there's a possible 'intermediate form', Peripatus, the velvet worm, being long, thin and soft-skinned, but also having many stubby legs!