Umbonium, sometimes known as the "button top shells", is a genus of sea snails, marine gastropod molluscs in the family Trochidae, the top snails.[2]
The shells of the species in this genus are low-spired and shaped like a button. The orbicular shell is depressed and imperforated. It is polished, porcellaneous and has a very thin pearly layer inside. The whorls are flattened above, bright, smooth or spirally grooved. The small, transverse aperture is wider than high. The thin outer lip is acute. The inner lip is rounded, ending in a simple point. The umbilicus of the shell is often completely covered with a thick and smooth callus.[3]
The animal has a distinct lateral fringe of the foot, with three filaments on each side. The front of the right side near the base of the tentacles is produced into a fleshy lobe. The right tentacle is free, with the eye-peduncle compressed, and bears a rudimentary eye. The left eye-peduncle is cylindrical, with a distinct eye, and furnished with an expansion or frontal lobe, which is folded on itself and fringed at its free margin. The operculum is horny, orbicular, and multispiral.[4]
Species in the genus Umbonium include:
Umbonium, sometimes known as the "button top shells", is a genus of sea snails, marine gastropod molluscs in the family Trochidae, the top snails.
Umbonium is een geslacht van weekdieren uit de klasse van de Gastropoda (slakken).
Umbonium is een geslacht van weekdieren uit de klasse van de Gastropoda (slakken).
Umbonium là một chi ốc biển trong họ Trochidae.[2]
Umbonium là một chi ốc biển trong họ Trochidae.
䗉螺屬（学名：Umbonium）是原始腹足目钟螺科的一個屬，是䗉螺亞科的成員之一[2]，其棲息地在海裡。
以下為部份屬於本屬的物種[3]：
