Spatangina
plural noun
Spat·an·gi·na
ˌspatᵊnˈjīnə,
-jēnə
: a suborder of sea urchins (order Exocyloida) comprising numerous more or less flattened approximately heart-shaped sea urchins that exhibit considerable secondary bilateral symmetry compare clypeastrina
Word History
Etymology
New Latin, from Spatangus + -ina