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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. 72. 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. V. 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.

coast of Northumberland. This fragment is about five feet high, and two feet three inches in diameter at its base. Scale one-twenty-fourth. (Sopwith.) 2. Fragment of the bark on the trunk of a Sigillaria, from Earl Fitzwilliam's coal-mine at Elsikar, near Rotherham. In this mine many large trunks are seen inclined in all directions, and some nearly vertical. (See V. I. p. 353, Note.) The bark is converted into a thin lamina of coal, and remains attached to the lower portion of this specimen. It exhibits on its outer surface scars formed by the articulations of the bases of leaves; these are penetrated near their centre by three apertures for vessels that passed from each leaf into the trunk. The decorticated upper part of this specimen presents an impression of its striated internal surface, and exhibits beneath each scale two oblong parallel apertures, through which the vessels from a leaf penetrated the trunk. Scale one-half. (Original.)

The substance of the trunk must have been in a state of decay, before the mud, which is now hardened into shale, could have entered the interior of the bark. When trunks of this kind are inclined at an angle exceeding 45°, they are usually distended with sandstone, or sandy shale; when at a less angle than 45°, they are most commonly compressed, and have only a thin flat portion of shale, formed of indurated mud within their bark. The bark, wherever it has not perished, is converted to coal.

2'. Articulating leaf-scar on the exterior of the bark of another large trunk of Sigillaria from Elsecar. Nat.

* M. Ad. Brongniart found a stem of Sigillaria in a coal-mine at Essen in Westphalia, which was dichotomous near its top.

size. On comparing this scar with those upon the bark of Fig. 2, it may be seen that the different modes of articulation of the leaves with the cortical integument present obvious characters, on which specific distinctions may perhaps most easily be established, in this very obscure and curious family of extinct plants. See various figures of these leafscars in Lindley and Hutton's Fossil Flora, Plates 55. 56. 57. 71. 72. &c. In Figs. 2, and 2', as in many other species, decurrent lines are visible on both sides of the scar. (Original.)

Fig. 3. Ulodendron Allanii, (nobis) scale one-fifth. See V. I. p. 356. Note. Drawn from a plaster cast of an impression on sandstone, in the Museum of the Royal Society of Edinburgh from the Coal formation at Cragleith. This sandstone has formed a natural mould on the outer surface of a stem, which has entirely perished; our cast gives a fac-simile of the small rhomboidal scales, and of three large round scars on the exterior of the trunk. This impression has been figured, in an inverted position, by Mr. Allan in Vol. IX. Trans. Royal Soc. Edin. 1823. Pl. XIV. p. 236. (Original.)

Our figure represents the trunk in its natural position. In the centre of each scar is a cavity, indicating the place of attachment of a cone. The upper portion of each scar is marked with furrows, produced by pressure of the long radiating scales at the bottom of the cone. This pressure has nearly obliterated the smaller rhomboidal scales of the bark, in those parts where the furrows are deepest; on the lower portion of the scars, the scales of the bark have been but slightly modified by pressure of

the cone.

Fig. 4. A single scar formed by the attachment of a cone

of another species, Ulodendron Lucasii, (nobis,) discovered by Mr. Lucas in the S. Wales Coal field near Swansea. Some scales and speared-shaped leaves of the trunk are still preserved around the margin of this scar. As the bark has fallen off, we have only the impression of its inner surface. This surface exhibits small apertures, through which vessels entered from beneath the bark-scales into the trunk. On the upper part of the disk, the traces of many of these vessels have been obliterated by pressure of the Scale one-fourth. (Original.)

cone.

Fig. 5. Ulodendron Stokesii. (nobis.) A large oval scar, 44 inches in its longer, and 3 inches in its shorter diameter) preserved in shale from an unknown locality in the English Coal Formation. On the margin of this scar are the remains of rhomboidal scales, and impressions of scales, and a few small leaves. Within the disk a few fragments only of the bark remain near its upper margin. Near its centre, is the mark of the insertion of the stem of a large cone. The lower half exhibits a series of small tubular cavities, marking the place of vessels which passed from the bark into the trunk, one beneath each of the bark-scales that have fallen off. In the upper half of the Scar, there are but slight traces of these cavities, and the surface is marked with furrows, produced by pressure of the long radiating scales of the base of the cone. Scale one-fifth. (Original.)

Fig. 6. Ulodendron Rhodii. (nobis.) Scar on a scaly stem, from the Coal field of Silesia, figured by Rhode in his Beitrage zur Pflanzenkunde der Vorwelt, L. 2. Pl. 3. Fig. 1. The lower portion of this Scar

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