ambulacrum

ambulacrum (noun; plural ambulacra; Latin ambulare, to walk): 1. (Arthropoda: Chelicerata) The adhesive disc of hooks that terminate the tarsus of ticks.

2. (Arthropoda: Insecta) The walking leg.

3. (Echinodermata) Plates with pores forming the test, arranged in 5 or more rows, where the podia of the water-vascular system project to the exterior.