Nucula is a genus of very small saltwater clams. They are part of the family Nuculidae.
Goniasteridae constitute the largest family of sea stars, included in the order Valvatida. They are mostly deep-dwelling species, but the family also include several colorful shallow tropical species.
Coelopleurus is an extant genus of echinoids with fossil records dating back to the Eocene, with remains found in Europe and North America.
Argopecten is a genus of saltwater clams, or scallops, marine bivalve mollusks in the family Pectinidae.
Cidaridae is a family of sea urchins in the order Cidaroida.
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.
Dendraster is a genus of sand dollars of the family Dendrasteridae within the order Clypeasteroida. The extant species in this genus are found in the northeast Pacific Ocean from Alaska to Baja California. The best-known, most common and widespread species is D. excentricus.
The Oreasteridae are a family of sea stars in the class Asteroidea.
Toxopneustidae is a family of globular sea urchins in the class Echinoidea.
Clypeaster, common name "cake urchins" or "sea biscuits", is a genus of echinoderms belonging to the family Clypeasteridae.
Astroboa is a genus of basket stars in the class Ophiuroidea.
Schizaster is a genus of heart urchins belonging to the family Schizasteridae. The type species of the genus is Schizaster studeri.
Stylocidaris is a genus of echinoderms belonging to the family Cidaridae.
Ammotrophus is a genus of echinoderms belonging to the family Clypeasteridae.
Cassidulus is a genus of echinoderms belonging to the family Cassidulidae.
Metalia is a genus of echinoderms belonging to the family Brissidae.
Echinolampas is a genus of echinoderms belonging to the family Echinolampadidae.
Ophiomusa is a genus of echinoderms belonging to the family Ophiolepididae that includes: sea urchins, sand dollars and sea cucumbers. Ophiurida are similar to starfish; they both have a central disc and five arms sprouting from the disc. One of the main distinguishing factors of an Ophiuroid is its arms; the arms of an Ophiurida are longer, thinner, and distinctly separated in comparison to those of a sea star.
Encope is a genus of echinoderms belonging to the family Mellitidae.
Paleopneustina is a suborder of sea urchins of the order Spatangoida. Its taxonomy is still under investigation.
