Diagnostic characters
Shell conical, not spirally coiled except in the protoconch, sharply pointed. Aperture nearly circular; an internal tongue-shaped partition is present. A flattened neck lobe on each side of the head behind the tentacles. No operculum on foot.

Other characters
The protoconch is usually eroded. The only ornament takes the form of growth lines parallel to the edge of the aperture, sometimes, especially near the aperture, with small projections. The internal septum arises from a curved base running from apex to apertural edge and is narrow at the former end, broad at the latter. White or yellow. Up to 15 mm across, 5 mm high.
The head is elongated posterior to the tentacles, the snout being rather short and broad. The left neck lobe bears a ciliated groove which runs from the mouth to a pouch in the thick mantle edge overlying the head; that on the right is crossed by a ciliated groove originating on the floor of the mantle cavity. Animals up to a shell breadth of 2 mm are male and have a bilobed penis behind the right tentacle; larger animals are females in which the penis becomes reduced to a knob above the tentacle (Wyatt, 1960). The foot is large, oval in outline. The flesh is yellow, speckled with white.
C. chinensis is a ciliary feeder, trapping particles on a mucous sheet on the ctenidium; this is then rolled up and passed along the groove on the floor of the mantle cavity to the mouth (Werner, 1952, 1953, 1959). The animals may be found on shells or under stones on sheltered shores in southwest England and sublittorally in the western Channel, off the Isle of Man and in the Firth of Clyde.
Eggs are laid in soft capsules, 12-25 in each, attached to stones and brooded under the foot of the female. Development is direct (Lebour, 1936).

Calyptraea chinensis
Habitat: it lives on stiff substrata associated with muddy bottoms and on shells (Ostreidi etc.) in the infralittoral and circalittoral zones.
Distribution: it can be found all over the Mediterranean. Common enough.
Notes: quite typical shell patelliform in aspect, conic (Chinese hat), slight, more or less elevated, with a circular base adjusting itself to substratum, apex central. Internally it is crossed by a lamina thin, helicoidal, rather elevated, that, from the centre of shell, reaches the margin. External surface wrinkled and crossed by strong growth striae. There are often present lamellous papillae more evident at the margins, inside bright, margin rounded. From yellow-grey to hazel-brown in colour either with streaks or flammulae brown in colour. Notwithstanding patelliform aspect this species has not a radial development but growth occurs according to a spiral. This species has not a pelagic larval phase. Veliger phase is passed into capsules fixed to substratum and preserved under the shell. Protoconch is protuberant, smooth, bright and yellowish in colour. Among the most known synonyms of this species we remind: C poll, C. squamulata, C. laevigata, C. muricata.
Average measures of adult specimens are around 12-15 mm in diametre by 5-6 mm in height.