Intermediate valves on 56 mm long specimen. Split, Croatia. July 2012. © Prkić.
The visible intermediate valves occupy only 30 to 40% of the chiton’s width; width of valve (4) narrower than girdle to one side of it (5).
A broad girdle extension from each side passes between the valves (1).
When the animal is adhering to the substrate, the girdle extensions meet (2) or are only separated by the narrow jugal area measuring about 5% of the animal’s width (3).

KEY ID FEATURES : 01 Acanthochitona fascicularis