| These are broad concavities in the ambitus that could be considered precursors to the ambulacral notches of certain mellitids. |
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| The ambulacral grooves are narrow and the ambulacral ossicles are not exposed. |
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| The longest ambulacral column is parallel and adjacent to the ambulacral-adambulacral furrow. |
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| Its wide ambulacral grooves and open filtration fan made it adapted for motile particle capture in a wide variety of environments. |
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| Modified ossicles called lappets that border the ambulacral groove function to close off the groove and prevent damage to the tube feet. |
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| Interadambulacral contact facets lie beneath the ambulacral and overlie tissue depressions for the longitudinal muscles that lower the arm. |
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| In asteroids, the ambulacrals arch to form a deep ambulacral groove. |
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| Notches are ambulacral lunules that form close enough to the ambitus that the ambitus is unable to close over the distal part of the notch to form a closed lunule. |
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| Further, adambulacralambulacral articulation is distinct between Zoroaster and the superficially similar Paleozoic species, and ambulacral form also is distinctive. |
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| In the Paleozoic era, brittle stars had open ambulacral grooves, but in modern forms, these are turned inward. |
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| The test is rigid, and divides into five ambulacral grooves separated by five interambulacral areas. |
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| They also have statocysts, called spheridia, located within the ambulacral plates to help the animal remain upright. |
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| Proximal ambulacral pairs can be partially separated, forming a buccal slit, an expansion of the mouth frame. |
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| They are essentially fused plates which correspond to the parallel ambulacral plates in sea stars and five Paleozoic families of ophiuroids. |
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| Sea urchins' tube feet arise from the five ambulacral grooves. |
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