Assertion: sand dollar's test | /r/HasProperty | internal skeleton
Facets:
Source sentences:
text: Sea urchin, any of about 950 living species of spiny marine invertebrate animals (class Echinoidea, phylum Echinodermata) with a globular body and a radial arrangement of organs, shown by five bands of pores running from mouth to anus over the test (internal skeleton).
text: Some species found stranded on the shores of North America have five or six slots, or lunules, through the test (external skeleton).
text: In many species the hollow, slightly elongated test (internal skeleton), which accommodates the water-vascular system, is symmetrically notched on the edge or has narrow perforations (lunules).