The term sand dollar refers to species of extremely flattened, burrowing sea urchins belonging to the order Clypeasteroida. Some species within the order, not quite as flat, are known as sea biscuits.
Loveniidae is a family of heart urchins in the order Spatangoida.
Echinocardium is a genus of sea urchins of the family Loveniidae, known as heart urchins.
Arachnoididae is a family of echinoderms of the order Clypeasteroida.
Crambinae is a large subfamily of the lepidopteran family Crambidae, the crambid snout moths. It currently includes over 1,800 species worldwide. The larvae are root feeders or stem borers, mostly on grasses. A few species are pests of sod grasses, maize, sugar cane, rice, and other Poaceae. The monophyly of this group is supported by the structure of the tympanal organs and the phallus attached medially to the juxta.
Stolidobranchia is an order of tunicates in the class Ascidiacea. The group includes both colonial and solitary animals. They are distinguished from other tunicates by the presence of folded pharyngeal baskets. This provides the etymology of their name: in ancient greek, στολίς, ίδος means the "fold" of a cloth. Stolidobranchian sea squirts are also characterized by the complete absence of an abdomen. The abdominal organs of other tunicates are instead located to one side of the pharyngeal basket in this group.
The heart urchins or Spatangoida are an order of sea urchins.
Cidaroida is an order of primitive sea urchins, the only living order of the subclass Perischoechinoidea. All other orders of this subclass, which were even more primitive than the living forms, became extinct during the Mesozoic.
Spatangus is a genus of heart urchins in the Spatangidae family. The genus is synonymous with the previously recognised genera Prospatangus Lambert, 1902 and Spatagus. There are nine recognised species. The type species is Spatangus purpureus Müller, 1776 by subsequent designation.
Irregularia is an extant infraclass of sea urchins that first appeared in the Lower Jurassic.
Schizaster is a genus of heart urchins belonging to the family Schizasteridae. The type species of the genus is Schizaster studeri.
Amblypneustes is a genus of sea urchin, belonging to the family Temnopleuridae.
