Wikipedia
Ceratophyllidia
Ceratophyllidia is a genus of sea slugs, dorid nudibranchs, shell-less marine gastropod molluscs in the family Phyllidiidae.
They are known for their unusually soft, spherical and stalked tubercules on their upper dorsa. Unlike the species of Phyllidia, they lack oral glands or the glands are free from the oral tube.