Cornwall, U.K. 1984. Granules on dorsal surface of valve magnified X100 by scanning electron microscope. Specimen RMNH.MOL.HLS.1197 coll. Naturalis, Leiden, Netherlands. Image provided by J. D. Sigwart.
Scale line 0.1mm. Frame width 1.2mm.

Flat-topped granules (1) are widest and tilted up at anterior.
Each granule has
2: a single megalaesthete (large pore with underlying canal)
surrounded by
3: 12 to 25 smaller micraesthetes.
In life, the canals in chiton species are filled with aesthetes (sensory tissue) that variously may include light sensors, chemoreceptors, mechanoreceptors, replenishment of properiostracum materials, and secretion of protective substances in different species.
Chitons have no eyes or sensory tentacles on the head.
More highly magnified image at 8Ac flic.kr/p/NptSr7 .

KEY ID FEATURES and similar species at: 01 Acanthochitona crinita