Sea Butterfly - Corolla spectabilis
Commonly referred to as Sea butterfly and also as Spectacular Corolla, Corolla spectabilis (Gastropoda - Thecosomata - Cymbuliidae) is a species of planktonic sea slugs, belonging to a group which are collectively called pteropods.
Corolla is characterized by having a single wing plate (those structures resembling wings), and a gelatinous internal pseudoconch which contains the visceral mass. The pseudoconch can grow to about 8cm in length in large animals, with a wing plate span of 16cm.
One of the most interesting features of these sea butterflies is their method of feeding. They produce a mucous web, many times the size of the animal and can have a diameter of about 2m, to entangle and trap planktonic food.
Photo credit: ©Arne Kuilman | Locality: Philippines (2013)