is flatter; and there is scarcely any trace of a ball. The greatest diameter of the constricted part of the centrum is 2 inches ; the neural pedicles become more elongated, measuring 2 inches. After the 13th the centrums get rapidly smaller. The 15th is distinctly biconcave; the centrum is somewhat compressed laterally; the neural canal is narrower, with a concave channel in the centrum, margined by shorter pedicles. The 16th is 4 inches long. The 20th is 4 inches long, has the centrum 2 inches wide posteriorly, and, as preserved, is 24 inches deep. The least diameter of the centrum where most constricted is 13 inch. The articular ends are greatly flattened, but slightly concave, as in many Plesiosaurs. The pedicles for the neural arch remain at one inch from the anterior margin; the extreme external width across the pedicles is 13 inch; the width of the neural canal is inch; the antero-posterior extent of the pedicles is 1 inch. Between No. 23, the last of the Barnwell series, and 24, the first of the Barton series, a few are probably lost. The Barton portion of the animal is in rather better preservation, though a few of the vertebræ, which have been washed with the phosphatic nodules in the mill, show curiously how the circumstances under which fossils are collected may modify their appearance. In No. 24 the centrum is 3 inches long, and 2 inches deep in front; the anterior articulation is deeply cupped; and the posterior articulation somewhat approximates to a ball. The least diameter of the middle of the centrum is less than 1 inch. The pedicles are now placed nearly in the middle of the length of the centrum. No. 25 is 34 inches long, with the articular ends 23 inches in diameter; they are deeply cupped with a central deeper depression. The next vertebra has the articular ends much flatter, with a transverse depression which does not appear to result from pressure. No. 28 is 34 inches long, and has pits in the neural canal like foramina for blood-vessels. No. 30 has the centrum anteriorly deeply concave; posteriorly it is subconvex with a transverse groove. No. 35 is 22 inches long. The posterior articulation is convex with a slight central depression; as preserved it is 1 inch wide. The centrum is compressed from side to side, measuring inch in least diameter; the anterior articulation is very irregular. The neural canal is about inch wide. The pedicles are compressed, inch wide and 1 inch long.

A few neural arches are preserved. They are remarkable for great antero-posterior extent, compression from side to side, and absence of a neural spine, the superior margin being concave from front to back, and only rising two inches above the top of the neural canal in the deepest specimen. In that example the posterior zygapophysial facets are preserved. They are inch in diameter, and are raised like wafers on the inferior margin of the specimen so as to look outward and downward. The median posterior portion of the arch is prolonged for some distance behind the facets; anteriorly the arch is forked. Further back in the tail, where the arch is more depressed, the articular facets are lost; but the posterior process, ovate in section, is still directed for some distance upward

and backward, and terminates in a rounded end. The length of the neural surface on a large neural arch is 23 inches.

The irregularity of the articulation of the centrums seems characteristic; for in a second series of three large vertebræ, two are procœlous and the third is biconcave.

Two or three small vertebræ were also found about 1859 at Barnwell. One of these (figs. 1 & 2) retains the neural arch, and shows an indication of the separation between the neural arch and centrum. It is 25 inches long at the superior part of the centrum, and a little less at the base. The anterior articulation (fig. 2) is subconcave and

irregular; the posterior is subconvex, with a transverse impressed groove (fig. 1). The articular margin is somewhat worn; but on the base the centrum is somewhat flattened, and on one side posteriorly there is a faint slight ridge such as might indicate a chevron bone, had there been any other reason for suspecting such a structure. The neural arch seen from above (where it is worn) is wedge-shaped, 1 inch wide in front, with the straight sides converging posteriorly in a distance of 13 inch to an inch. The superior surface of the arch is flattened, and rounds into the sides; it is straight and inclined forward; but the extremities of the processes are broken both before and behind. In front the height from the base of the eentrum is 17 inch; 1 inch further back the height is 2 inches. The antero-posterior extent of the pedicles of the neural arch between the concave notches in front and behind it is 1 inch. The centrum is 14 inch deep at the posterior articulation, while in the middle of the neuro-central suture it is 1 inch deep.

In the Annals of Natural History' for November 1871, I described and figured under the name of Acanthopholis platypus the metapodium of a large animal. As the middle bone is 6 inches long, and the bones measure 9 inches over their proximal ends from side to side, and there is no other evidence of bones of Acanthopholis reaching a corresponding size, I am inclined to speculate on the probability of those bones being a part of the foot of Macrurosaurus, probably the metacarpal bones. If the remains both belong to the same genus, then Macrurosaurus would probably indicate a gigantic modification of the Crocodilian type of Dinosaurs.

48. On REMAINS of EMYS HORDWELLENSIS (Seeley) from the LOWER HORDWELL BEDS in the HORDWELL CLIFF, contained in the Woodwardian Museum of the University of Cambridge. By HARRY GOVIER SEELEY, Esq., F.L.S., F.G.S., &c., Professor of Geography in King's College, London. (Read June 21, 1876.)

By the intervention of Mr. Henry Keeping the Woodwardian Museum acquired in 1868 some fine Chelonian fragments mineralized nearly black (now arranged on shelf d of case 109)-which after a little effort I found to reunite themselves into a plastron from which the xiphoid bones are lost, and a large connected part of the carapace which comprises the nuchal plate and the two adjacent marginal plates, the first six neural plates, and portions more or less perfect of the first five pairs of costal plates. marginal plates are all or nearly all lost, having probably been washed away by the sea while the specimen was lying on the shore. Two disconnected marginal bones were collected with the other remains.

The

Mr. Keeping tells me that the horizon of the fossil is about 20 feet below the bed which yields the chief remains of Crocodilus Hastingia, and about 10 feet above the brackish-water Upper Bagshot beds, which are seen in the cliff rising westward at an angle of 3° at Mead End; so that the position of the specimen is low down in the Lower Hordwell series.

The fragment of carapace as preserved is 9 inches long and 6 inches broad; so that when perfect it probably measured about 12 inches in length and nearly 10 inches in breadth. In length it is gently inflated, so that in the portion preserved (nine inches) the highest part of the curve rises more than an inch above a base-line drawn from the ends of the specimen. As is usual, the transverse section is more inflated; and in the width of 6 inches the highest part of the curve rises 14 inch above a base-line drawn from the two sides. The carapace is impressed with a small subtriangular nuchal scute, the first and part of the second marginal scute on each side, the first, second, third, and part of the fourth vertebral scutes, and parts of the first, second, and third pairs of costal scutes. I will first give the characters of the scutes, and then describe the forms of the skeletal osseous plates.

The Scutes of the Carapace.

The nuchal scute (fig. 1, nu) is small, has its margins sinuous, is inch in length, measures inch in breadth behind, and is inch wide on the anterior margin of the carapace. The first vertebral scute (v 1) is six-sided and subpentagonal, three of the sides being in front of the scute, there being a median side behind the nuchal scute, and two lateral margins in which it joins the first marginal

scute on each side of the nuchal scute. It is 24 inches long in the median line, 27 inches broad at the anterior lateral angle (where it meets the first marginal and first costal scutes), and 14 inch broad along the sinuous transverse posterior line (in which it meets the second neural scute). Like all the other scutal areas, both of the carapace and plastron, it is marked with subparallel impressed concentric lines indicative of the intermittent growths of the scutes. These lines are least distinct on the posterior border.

The first vertebral scute extends transversely beyond the nuchal plate (which is 23 inches broad) so as to impress the angles of the

nu. Nuchal scute. v1, v2, v3, v 4. First, second, third, and fourth vertebral scutes. c1, c2. First and second costal scutes.

marginal plates. The scutal area is convex in length as well as in width; its posterior border impresses the first neural plate at less than half an inch in advance of its posterior sutural border.

The second vertebral scute (v 2) is nearly square, being about 24 inches long and nearly 24 inches broad. The two pairs of sides, which are somewhat sinuous, are subparallel; and the area is convex in length as well as in width. Its anterior and posterior borders cross the first and third neural plates, while its lateral borders cross the first, second, and third pairs of costal plates.