Description
The shell is strong in the whorls quickly get larger. The shell is flat-topped and the opening is oval. The whole shell shows thin growth lines. The oval eggs are laid in a translucent to yellow gelatinous masses, on sea weeds.

Size
Up to 18 mm.

Colour
Yellow, orange, brown of green and occasionally with a colour pattern on the shell. The animal itself is yellow to yellowish brown.

Habitat
In the tidal zone on hard substrata and sea weeds.

Distribution
North eastern Atlantic from Norway till western Mediterranean.