Cymbulia peronii

Cymbulia derives from the Latin cymbula, meaning “small boat,” while peronii honors François Péron (1775–1810), a French naturalist who, after being wounded and imprisoned during the wars against Prussia, studied medicine and natural history and later served as a ship’s doctor aboard Le Géographe on the 1800–1804 expedition to Australia, collaborating extensively with Charles-Alexandre Lesueur.^[3]

The species inhabits waters concentrating around the extreme south-east United States, the Balearic Islands of Spain, Svalbard, and the offshores of Namibia, sometimes down to about 2,000 m (6,560 ft) depth, carried by currents.^[3] It can withstand temperatures of 13–27 °C (55–81 °F). ^[4]

It reaches about 60–65 mm (2.4–2.6 in) in length and has a translucent, bluish body with two wing-like parapods used for slow movement. During development it retains a transparent, cartilaginous internal shell (pseudoconch) with five dentate ridges that resembles a “glass slipper” ^[5] or gelatinous crystal-like structure often found washed up on beaches after the animal’s death, sometimes called a "venus' hoof".^[4]

Cymbulia peronii often captures prey by having its oral organs open while drifting, and feeds on phytoplankton, mucus, diatoms and other chromists.^[6] It is a passive predator, and utilizes hair-like tentacles to sense and detect nearby prey.^[4]

Reproduction and breeding takes place temporally from June to August. The animals are protandrous hermaphrodites, meaning male characteristics develop first, with individuals becoming female as they age; this is known as successive hermaphroditism. Reproduction takes place in the planktonic environment through the release of gametes and the development of veliger larvae (gastropod larvae).^[4]