PLATE XLVII.
Fossil Remains of Crinoidea.
In this beautiful plate Mr. Parkinson has figured a great variety of ossicula and portions of stems belonging to many species and genera of Crinoidea; the markings or sculpturing on the articulating surfaces of the columnar ossicula are represented with great accuracy. It is not within the plan of this work to give detailed descriptions of these numerous detached parts; a few of the most interesting objects only will be particularized.
The specimens figured in the upper part of the plate, figs. 1 to 28, are cylindrical ossicula, and portions of stems of Encrinites: those in the lower division are for the most part pentagonal, and therefore belong to Pentacrinites.
Fig. 24. The "Tortoise Encrinite," of Mr. Parkinson, (Marsupites Milleri, of Mantell,) from the chalk of Kent. The specimen figured is the receptacle or body of a very remarkable crinoideal animal which forms the link that unites the Lily-shaped animals with the Star-fishes; like the former, the receptacle is composed of articulated plates, closed at the top by a tessellated plate-work with a buccal aperture, and surrounded by five flexible arms; but the original animal, like the Star-fishes, was destitute of a stem, and could float through the water at pleasure. Its true structure was first pointed out by me in 1822;[39] the name Marsupite was suggested by the purse-like form. In the figure, the base of the receptacle is uppermost. Fig. 30, is a single plate of a Marsupite attached to a piece of chalk.
[39] See "Fossils of the South Downs."
Figs. 31, 35, 38, 39, 40, 41, 74, 75, 76, 77. These are portions of a small species of Encrinite (Apiocrinus ellipticus) peculiar to the white chalk, in some localities of which the detached ossicula and peduncles are abundant. At Northfleet, near Gravesend, these fossils are often met with. Figs. 75, and 76, are portions of the receptacle with part of the column; figs. 31, 38, and 39, are parts of the processes of attachment. I have never seen any specimen with the arms.[40]
[40] Medals of Creation, p. 321.