The word „nudibranch“ comes from the Latin nudus, naked, and the Greek βρανχια, brankhia, gills. Nudibranchs occur in seas worldwide, zoologischer Anzeiger, 1889, Vol. 12 PDF from the Arctic, through temperate and tropical regions, to the Southern Ocean around Antarctica. Nudibranchs are benthic animals, found crawling over the substrate.
Författare: J. Victor Carus.
The eyes in nudibranchs are simple and able to discern little more than light and dark. The eyes are set into the body, are about a quarter of a millimeter in diameter, and consist of a lens and five photoreceptors. In most species is a swimming veliger larva with a coiled shell which is shed at metamorphosis when the larva transforms into the adult form. In the course of their evolution, nudibranchs have lost their shells, while developing alternative defense mechanisms. Another method of protection is the release of an acid from the skin. Once the specimen is physically irritated or touched by another creature, it will release the mucus automatically.