It is very thin and leaf-like, broadly oval in outline, with a thickened central ridge and a lobed, wavy margin.

[2] Yungia aurantiaca is a predator, feeding on tunicates, bryozoans and other small sedentary invertebrates.

When one flatworm has successfully "stabbed" another, sperm is injected and finds its way through the body to the oviducts, where the eggs are fertilised.

The flatworm also has great regenerative powers, and if its fragile body is torn into pieces, the sections can grow into viable individuals.

[2] Yungia aurantiaca can creep over surfaces using muscular contractions and the beating of cilia.