Description
English: This Glaucilla marginata was washed up on Surfers Paradise Beach in Queensland Australia.
Date 24 May 2009, 11:14 (UTC)
Source Glaucus_atlanticus_1.jpg
Author https://commons.wikimedia.org/wiki/File:Glaucus_atlanticus_1.jpg : Taro Taylor from Sydney, Australia; derivative work: dapete https://commons.wikimedia.org/wiki/User:Dapete
Source: https://en.wikipedia.org/wiki/File:Glaucilla_marginata.jpg

Glaucus marginatus is a species of small, floating, blue sea slug; a pelagic aeolid nudibranch; a marine opisthobranch gastropod mollusk in the family Glaucidae. This species is closely related to Glaucus atlanticus. This species is pelagic, and can be found in the Pacific Ocean. These small nudibranchs float upside down on the surface tension in temperate and tropical seas. They eat colonial cnidarians such as the Portuguese man o' war. This nudibranch is dark blue, and in many ways it resembles a smaller version of Glaucus atlanticus. However, in this species the cerata are arranged in a single row in each arch. Order: Nudibranchia, Superfamily: Aeolidioidea, Family: Glaucidae, Genus: Glaucus, Species: Glaucus marginatus (Bergh, 1860)
Synonyms:
Glaucilla briarea Bergh, 1860
Glaucilla marginata Bergh, 1860 (original combination)