Fig. l. Recent Pentacrinus Caput Medusæ, from the bottom of the sea, near the I. Nevis, in the W. Indies, reduced from the Figure in Miller's Crinoidea, P. 48, Pl. I. In the front of this Figure, two of the arms with their hands and fingers are much smaller than the others, and shew that these animals, when mutilated, have the power of reproducing lost parts.

D. Auxiliary side arms, articulating at distant intervals, with the vertebral column; these also, when mutilated, are reproduced.
a/F First costal plate.
b/F Second costal plate.
H. Scapula.
I. Interscapulary joint.

Miller's description of this recent Type, of a family [085] of which a few individuals only have hitherto been found, affords examples of many very delicate and beautiful mechanical contrivances, which throw important light on corresponding parts of the fossil species of this, and of kindred genera that abound in strata of the Secondary series, and more especially in the Lias. (See V. I. pp. 432. 433. 436.)

Fig. 2. Pentacrinus Europæus, discovered in the Cove of Cork, and on other parts of the coasts of Ireland, by J. V. Thompson, esq. (See V. I. p. 432.) In this figure several Individuals in different stages of development, adhere by the base of an articulated column to the stem of a Coralline.

Fig. 2'. One of the Individuals magnified and fully expanded. See V. I. p. 433.

Mr. J.V. Thompson has more recently conjectured that the Pentacrinus Europæus, which in early life is fixed by its stem to other bodies, is produced from the ovum of the Comatula, and becomes afterwards detached, and forms a perfect Comatula, capable of moving freely in the Ocean; at one time crawling amongst submarine Plants, at others float ing, or swimming like Medusæ. (See Proceedings of Royal Society, London, June, 1835.)

Fig 3. Small Briarean Pentacrinite, adhering to a fragment of Jet from the Lias at Lyme Regis. (See V. I. p. 437, Note.)

Fig. 4. Fragment of the column of Pentacrinites sub-angularis. The Vertebræ are nicely articulated to admit of flexure without risk of dislocation. The uppermost joint d. shews the lateral cavities for the articulation of auxiliary side arms. (Gold fuss. Pl. LII. f. g.)

Fig. 5. Vertical Section of Fig. 4. In this Fig. and in [086] Fig. 4, the joints are of three degrees of magnitude; those at a. being the largest, those at c. the smallest and thinnest, and those at b. of an intermediate size. The edges of c. appear at the surface only upon the salient portion of the column, Fig. 4. (See V. I. p. 436, Note.)

Figs. 6, 7, 8, 9, 12, 13. Portions of the vertebral column of Pentacrinites basaltiformis. 6, 8, 12, shew the stellated crenulations on the articulating facets of different parts of the column; 7, 9, shew the tubercles on the exterior of each columnar joint, for the attachment of cortical contractile fibres. 13. d, shews the articulating facets of the auxiliary side arms. (Goldfuss.)

Fig. 10. Articulating facet of a columnar joint of Pentacrinites scalaris. (Goldfuss. Pl. LII. 3. h.)

Fig. 11. Fragment of a column of the same species. The joint d. bears sockets for the articulation of the side arms. The other joints have large tubercles for the attachment of cortical fibres. (Goldfuss, Pl. LII. 3.p.)

Figs. 14, 15, 16, 17. Articulating surfaces of joints in different parts of tile column in Pentacrinites subangularis. The mechanism of each star seems differently disposed, to modify the amount of motion required at their respective places in the column. The tubercular surfaces between the rays or petals of the star indicate the action of the intervertebral contractile fibres. (Goldfuss, Pl. LII. l. m. n. o. p.)