> The outside (or ‘edge’) of the occlupanid is often smooth, but many species sport palps, or tabs. These have unguessable purposes for mating, locomotion, defense, take your pick.

I propose that these palps or tabs are remnants of the reproductive cycle, vestigial points of contact in the budding process. This phenomenon can be observed in some other classes within phylum Plasticae, and I see no reason to assume it is not happening here.