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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 W. I. p. 328, Note.)

Figs. 6, 7, 8, 9, 12, 13. Portions of the vertebral column

Fig.

Fig.

of Pentacrinites basaltiformis. 6, 8, 12, show the

stellated crenulations on the articulating facets of
different parts of the column; 7, 9, show the tuber-
‘cles on the exterior of each columnar joint, for the
attachment of cortical contractile fibres. 13. d,
shows the articulating facets of the auxiliary side
arms. (Goldfuss.)
10. Articulating facet of a columnar joint of Pen-
tacrinites scalaris. (Goldfuss. Pl. LII. 3. h.)
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

Fig.

different parts of the 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. 1. m. m. o.p.)

PLATE 53. V. I. p. 327, Note, et seq.

1. 2. Upper parts of two nearly entire specimens of Briarean Pentacrinite, projecting in high relief from the surface of a slab, nearly two inches thick,

EXPLANATION OF PLATE 53. 87

and entirely composed of a mass of petrified Ossicula of the same species of Pentacrinite. The surface of these fossils is covered with a delicate film of Iron Pyrites, which gives them the appearance of beautiful Bronze. (Original.)

12. Continuation of the stem of Fig. 1. 2. Portion of the stem of Fig. 2.

The length of these stems when entire, was three or four times that of the fragments here remaining. Upon the stem 2", nearly all the side arms retain their places in the grooves on each side of the salient angles of the pentagonal column; they diminish in size as they approach its upper extremity. This is also distinctly seen at the upper end of the column of Fig. 1.

# First costal plate. Second costal plate. F. r.

Fig.

Fig. Fig.

Fig.
Fig.

Fig.

3. Portion of a third column retaining nearly all its
auxiliary side arms in their natural place.
3". Continuation of the same column deprived of the
side arms.
4. Portion of another column, with traces of a few
side arms rising from the lateral grooves.
4". Continuation of Fig. 4.
5. Fragment of another column, the joints of which
are so much bent without dislocation, as almost to
give the column the appearance of a spiral disposi-
tion.
6. Body of a Briarean Pentacrinite and summit of
its column, showing the interior of the ossicula that
surround the abdominal cavity.

E. Pelvis. # First costal Plate. From a specimen in the

Fig.

Oxford Museum. (Original.)
7. Fragment of a column in the collection of Mr.
J. Sowerby, showing the oblique articulation of the

Fig.

Fig. Fig.

base of the side arms, with the larger joints of the
vertebral column. See W. I. p. 331. Note. (Original.)
8. Magnified Section of a portion of a column in
the Oxford Museum. The joints, as in Pl. 52, Fig.
4, 5, and in Pl. 49, Figs. 3, 4, are alternately thicker
and thinner; with a third, and still thinner joint in-
terposed between them. See V. I. p. 327, Note.
(Original.)
8% Nat size of Fig. 8.
8”. Portion of a Column, showing the manner in
which the edges of the thinnest plates, c, are visible
along the salient angles only. In the intermediate
grooves the thicker plates, of the first and second
sizes, a, b, overlap and conceal the edges of the
thinnest plates, c. The principle of this mechanism
is the same as in Pentacrinites subangularis, Pl. 52,
Figs. 4, 5, and in Encrinites moniliformis, Pl. 49,
Figs. 3, 4; but the circular form of the column in
the latter, causes the smallest plate, c, to be visible
around its entire circumference. See W. I. p. 327,
Note. (Original.)
The bases of two side arms are seen in two of the
grooves, articulating with the uppermost large joint
of this column. On other large joints are seen the
sockets from which similar side arms have fallen.

Figs. 9, 10, 11, 12, 13. Various stellated forms on the

articulating surfaces of Vertebrae, preserved in the dislocated mass beneath Figs. 1, 2. These petalshaped, and crenated rays were probably adapted

to produce various degrees of flexibility, according

to their respective places in the column. The small
Vertebra on Fig. 13, is derived from another indi-
vidual. (Original.)
The aperture at the centre of all these Vertebrae
was for the passage of the alimentary canal, which

Explan ATION OF PLATE 54. 89

Miller considers to have sent off ten branches at every joint, five to the interior and five to the exterior of the petals. Fig. 14. One of the largest auxiliary side arms. Some of these contained more than 100 joints. See V. I. p. 330. (Goldfuss.) a, b, c, represent different forms of the joints at different parts of the side arms, with their nicely adjusted articulating surfaces. Figs. 15, 16, a, b, &c. Various modifications of the articulating surfaces of the joints composing the fingers and tentacula. (Goldfuss, Pl. LI.) Fig. 17. Magnified extremity of one of the tentacula. The two last joints form a very delicate pair of pincers, to lay hold on its prey. (Original.)

PLATE 54. V. I. p. 333.

Fig. 1. Caryophyllia arbuscula, nat. size, with the animals expanded. (Mem. du Mus. d’Hist. Nat. Tom. 6, Pl. 15, f. 2.)

Fig. 2. The animal of Fig. 1. magnified; as seen from above.

Fig. 3. Vertical section of the cup of Meandrina labyrinthica, with the animal placed within it. (Mem. du Mus. d’Hist. Nat. Tom. 6, Pl. 16, 10 b.)

Fig. 4. a. The common Actinia, or Sea Anemone, expanded. b. The same contracted within its external skin. (Encyc. Method. Pl. 7.2. 6.")

Fig. 5. Madrepora gyrosa. (Ellis. Zooph. Tab. 51, Fig. 2.)

* This animal has no calcareous cell, but contracts itself into a tough fleshy sac, see Fig. 4. b. At a the Tentacula are represented in a state of expansion. Some of these Polypes present the same display of brilliant colours as many of those which construct persistent

calcareous cells.

Fig. 6. Section of the animal of Meandrina viridis, and of the coral in which it is placed. Fig. 7. Animals of Meandrina limosa as seen from above, and magnified; they are placed in confluent stellated cells similar to those in Fig. 5. Fig. 8. One of the same, seen in profile, with the edges of its coralline plates behind the tentacula. (Mem. du Mus. d’Hist. Nat. Tom. 6, Pl. 15. 4.) Fig. 9. Caryophyllia Smithii, from Torquay. Nat. size. Fig. 10. The same, with its animal partially expanded, within the centre of the coral. Fig. 11. The animal expanded and seen from above. (Zoological Journal, Vol. 3. Pl. 13.)

PLATE 55. W. I. p. 350.

Fig. 1. A. B. C. Trunk, and dichotomous branches of a fossil tree, Lepidodendron Sternbergii, found in the roof of a coal-mine at Swina, in Bohemia. (Sternberg, Tab. I.)

Fig. 2. The extremity of a branch with leaves attached to it, from ten to twelve inches long.” (Sternberg,

Tab. II.)

Fig. 3. Extremity of another branch, with indications of fructification somewhat resembling a cone. (Sternberg.)

PLATE 56. V. I. p. 352, et seq.

Extinct Plants from the Coal Formation.

Fig. 1. copied from a sketch by Mr. Sopwith, of the base of a large trunk of Sigillaria standing in 1803, in the cliff at Bog Hall, near Newbiggin, on the

* By an error in copying this figure the branches are made too broad in proportion to the leaves.

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