"This aeolid nudibranch is characterised by the slightly flattened cerata with brown patches (containing symbiotic zooxanthellae) on each side. It is a good mimic of its host, a soft coral of the genus Xenia. By contrast, Phyllodesmium longicirrum has much larger very flattened cerata with enlarged ends like paddles, and the brown zooxanthellae are arranged in rings."
Comment from Richard Willan
This aeolid nudibranch is characterised by the slightly flattened cerata with brown patches (containing symbiotic zooxanthellae) on each side. It is a good mimic of its host, a soft coral of the genus Xenia. By contrast, Phyllodesmium longicirrum has much larger very flattened cerata with enlarged ends like paddles, and the brown zooxanthellae are arranged in rings.