Unidentified Nudi from Tambulen, Bali

Unidentified nudi (or two species of nudi?) from Tabulen, Bali. These are tiny, tiny creatures, basically just floating around in the water column.

Difficult to say. My best guess is a Rostanga or a Sclerodoris but it's probably not a good guess.... It really looks like a sponge-mimic so it's puzzling to see it perched on hydroids, unless there's sponge surrounding the hydroid's stalks.