At least thirty pairs of elytra, scale-like modifications to the dorsal cirri, conceal the animal's body.

These are on alternate segments and do not meet dorsally, leaving the central line of the body uncovered.

A. vittata is a pale yellowish colour, with a few faint transverse bands, and a dark stripe located across segments 7 and 8.

[2] The species forms a commensal relationship with the gumboot chiton, living on its gills and pallial groove.

[4] Some other hosts have also been identified; these include the starfishes Henricia leviuscula, Luidia foliata, Pteraster tesselatus, Solaster stimpsoni and Solaster dawsoni and the abalone Haliotis kamtschatkana, as well as the terebellid worms Thelepus crispus and Neoamphitrite robusta.