Fig. 15, is a well known form, which occurs in thousands in the Oolite Limestone, the Coral Rag, of Caen, and other localities in Wiltshire; it belongs to a beautiful Cidarite (Cidaris Blumenbachii[51]), which is occasionally found with similar spines attached.
[51] See Wonders of Geology, vol. ii. p. 500, figs. 3 and 6.
Fig. 12. "A flat serrated spine from Verona."—Mr. Parkinson. It belongs to the Cidaris Schmidelii, of Goldfuss.
Fig. 7. The interior of the upper part or vertex of a large Echinus, from the tertiary strata of Malta. The greater portion of the shell is broken away, but a small fragment showing the outer surface remains on the upper left hand of the specimen. The five large petalous ambulacra are beautifully seen. Perfect examples of this echinite (Echinanthus Clypeaster altus, of Parkinson), are not uncommon.
Fig. 19. A spine of Cidaris sceptrifera, from the chalk of Kent.
Fig. 20. An elegant Turban Echinite, (Hemicidaris crenularis, of Lamarck,) common in the Coral Rag of Wiltshire. Groups of this beautiful echinoderm, with numerous spines attached, are found at Caen. I have seen on one slab of limestone, upwards of twenty individuals with the spines radiating round the shell, as if the animals were alive on a mud bank in shallow water.
Fig. 21. A fragment of the shell with two spines (Cidaris claviger), attached to a flint; from Kent.
Plate LVII.