EditorialNudibranchia or sea slugs: Hermaea bifida 1, Facelina auriculata coronata 2, Dendronotus frondosus 3, Okenia elegans 4, Doto coronata 5, Tritonia hombergii 6 and Ancula gibbosa 7. Chromolithograph by Adolf Glitsch from an illustration by Ernst Haeckel ...