"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…

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:…