"1. The whole animal with c, c, contractile vacuoles 2. Portion of periphery more magnified with a, four still pseudopodia and n, four nuclei or endoplasts. 3. A young actinosphærium."-Whitney, 1902

Actinosphærium

"1. The whole animal with c, c, contractile vacuoles 2. Portion of periphery more magnified with a,…

The spines are removed from most of the surface of this sand dollar.

Sand Dollar

The spines are removed from most of the surface of this sand dollar.

"A common European type of the group is the species Psammechinus esculentus. In certain forms the test is perforated by slit-like apertures." — Encyclopedia Britannica, 1893

Psammechinus esculentus

"A common European type of the group is the species Psammechinus esculentus. In certain forms the test…

"Rotula Augusti" — Encyclopedia Britannica, 1893

Rotula Augusti

"Rotula Augusti" — Encyclopedia Britannica, 1893

The most remarkable family of the Echinida are the <em>Sea-Eggs</em> or <em>Sea-Urchins</em> - <em>Cidaridae</em>: they consist of several species, somewhat varying in form, some being nearly flat, some oval, some heart-shaped, and some like the <em>Echinus esculentus</em>, resembling an orange in shape." &mdash; Goodrich, 1859

Sea-urchin

The most remarkable family of the Echinida are the Sea-Eggs or Sea-Urchins - Cidaridae:…

Sea urchin: the heavy projections are the spines; the long, slender ones are the tube feet.

Sea Urchin

Sea urchin: the heavy projections are the spines; the long, slender ones are the tube feet.