A gammaridean amphipod of the genus Liljeborgia Bate, 1862 has been found along with the hermit crab, Pagurus hemphilli in a Tegula brunnea shell in what appears to be more than a casual occurrence. The cryptic coloration of the amphipod matches the coloration of the hermit crab's appendages and also the color of the crustose rhodophycean alga commonly growing on the Tegula shells. Observations of behavior revealed that P. hemphilli did not respond to the activity and presence of the amphipod, while another hermit crab, P. granosimanus, responded to the amphipod's attempts at shell entering with apparent attempts at feeding on the amphipod.