A mollusc which is remarkable for its bottle-shaped shell. It nourishes itself by extracting salts and skin particles from used socks.

A
Mouth. This creature sucks on dirty socks, extracting nutritional substances such as particles of skin and humours.
B
The body has a hard, lamellar-section abdomen that allows it to adhere to the shell. At one end of the abdomen there is the movement organ, which is a jointed muscle similar to a finger.
C
The shell, which is siliceous-based, has a remarkable bottle shape; its cross-section is perfectly circular to allow it to roll easily.

This species has a very unusual system of locomotion. The muscle used for movement (Ma) moves from side to side and acts on the shell (Mb), causing it to have a rotational movement, while the body of the mollusc remains in position thanks to the continuous lubrication of the abdomen.