Intermediate valve (vi), ventral view. Length of live animal 26 mm. Llŷn, North Wales. March 2016.
Top of frame towards anterior of specimen.
White interior of valves is articulamentum, a thick layer of white aragonite, overlain in parts by myostracum, a thin discontinuous innermost layer only visible in section examined under microscope.
Articulamentum extends beyond dorsal pigmented tegmentum (see image 5Ac 05 Acanthochitona crinita ) to form large rounded apophyses (1) on anterior edge which extend in life under next valve forwards, and two lateral insertion plates, separated by single slit (2), that insert into girdle.
Beak (3) protrudes from posterior.

KEY ID FEATURES and similar species at: 01 Acanthochitona crinita