ambulacrum

[ am-byuh-lak-ruh m, -ley-kruh m ]

/ ˌæm byəˈlæk rəm, -ˈleɪ krəm /

one of the radial areas in an echinoderm, as the sea urchin, bearing the tube feet by which the creature moves.

Origin of ambulacrum

1830–40; < New Latin, Latin: alley, walking place, equivalent to ambulā- (stem of ambulāre to walk) + -crum noun suffix denoting means

am·bu·lac·ral, adjective in·ter·am·bu·la·crum, noun, plural in·ter·am·bu·la·cra.

In the starfish we noted five ambulacral areas, one on the under side of each arm; similarly we find five in the sea-urchin.

Elementary Zoology, Second Edition |Vernon L. Kellogg
Interambulacral areas: The five areas between the ambulacral zones.

The Sea-beach at Ebb-tide |Augusta Foote Arnold
In both cases also we find the ocular spots at the tips of the ambulacral areas.

Elementary Zoology, Second Edition |Vernon L. Kellogg
In this family the ambulacral plates have but three pairs of pores.

The Sea-beach at Ebb-tide |Augusta Foote Arnold

The same observations apply to smaller segments, and even to single detached rows of ambulacral feet.

Jellyfish, Starfish, and Sea-Urchins: Being a Research on Primitive Nervous Systems |G. J. Romanes

ambulacrum

/ (ˌæmbjʊˈleɪkrəm) /

any of five radial bands on the ventral surface of echinoderms, such as the starfish and sea urchin, on which the tube feet are situated

ambulacral, adjective

C19: from Latin: avenue, from ambulāre to walk