Ambulacrum (anatomy)

Sea urchin shell, or 'test'. Each white band is the location of a row of tube feet; each pair of white bands is called an *ambulacrum* There are five such ambulacra; the penta-radial symmetry reveals a kinship with sea stars.

In zoology, an ambulacrum is an elongated area of the shell of an echinoderm in which a row of tube feet are arranged.^[1]^[2] It is pluralized as ambulacra. The area on the shell between ambulacra is known as an interambulacrum.

^ Echinoderms through time. Bruno David, A. Guille, Jean-Pierre Feral. Boca Raton. 2020. ISBN 978-1-000-12367-8. OCLC 1228890101.{{cite book}}: CS1 maint: location missing publisher (link) CS1 maint: others (link)
^ Paul, C. R. C.; Smith, A. B. (November 1984). "The Early Radiation and Phylogeny of Echinoderms". Biological Reviews. 59 (4): 443–481. doi:10.1111/j.1469-185X.1984.tb00411.x. ISSN 1464-7931. S2CID 86572427.

[1] Echinoderms through time. Bruno David, A. Guille, Jean-Pierre Feral. Boca Raton. 2020. ISBN 978-1-000-12367-8. OCLC 1228890101.{{cite book}}: CS1 maint: location missing publisher (link) CS1 maint: others (link)

[2] Paul, C. R. C.; Smith, A. B. (November 1984). "The Early Radiation and Phylogeny of Echinoderms". Biological Reviews. 59 (4): 443–481. doi:10.1111/j.1469-185X.1984.tb00411.x. ISSN 1464-7931. S2CID 86572427.

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