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"A class of radiate animals, the highest in organisation of the great division of the animal kingdom. They have a digestive and a vascular system; for the former, however, there is in many of them only a single orifice; a circular and radiating nervous system has been observed in manyl they are especially characterised by their well-organised skin which in many is strengthened by calcareous plates, and in some also has the additional protection of numerous long spines. a, Asterias Tesselllata (Asteriadae); b, Spatangus (Echinidae) or sea-egg." — Chambers' Encyclopedia, 1875

Echinodermata

"A class of radiate animals, the highest in organisation of the great division of the animal kingdom.…

<i>Spatangus purpureus</i>. Illustration of the violet heart urchin. One half of the illustration shows the animal with the spines removed.

Violet Heart Urchin

Spatangus purpureus. Illustration of the violet heart urchin. One half of the illustration shows the…