apartment are placed on the shelves in the angle uniting Wall-cases A and B of the plan (ante p. 138). The following diagram will assist the visitor in finding the objects described. CASE marked CHELONIANS in Room III. :—

Upper Shelf.-Eningen Salamander.

Fossil Turtles from Harwich; Chelonia Harvicensis.

Turtles from the Isle of Sheppey.

Turtles from the Wealden of Tilgate Forest.

Vertebræ of Mosasaurus from Maestricht; and from the Chalk at Lewes.

Pterodactyle from
Lyme Regis.

Models of Pterodactyles.

Geosaurus Soemmeringii.
Two very interesting specimens
of the skeleton of this Crocodilian
reptile, from Monheim.

Two small cases with the jaws, teeth, &c. of the Geosaurus.

Platemys Bullockii.'— Wall-case A-B.-One of the most conspicuous of the fossil Turtles in the angle uniting the Cases A and B, is labelled as above; the specific name indicating its former possessor, the late Mr. Bullock, in whose museum in Piccadilly it was exhibited many years since.

This Turtle was discovered in the Eocene clay of the Isle of Sheppey; the plastron or floor is 16 inches in length and 14 inches in breadth, and is almost flat; the carapace is remarkably low. It belongs to the family of Marsh-Tortoises (Paludinosa) which much resembles the true Land-Tortoises (Testudinida.)

CHELONIA Harvicensis.—Wall-case A-B.-Two fine specimens, one exhibiting the inner surface or concavity, and the other the convexity of the carapace of a large marine Turtle, are placed in the centre of this compartment; they are from the Eocene argillaceous beds on the Essex coast. As remains of this Turtle were often found on the shore, near Harwich, my friend the late Mr. Samuel Woodward, figured and described the species as C. Harvicensis in a valuable work, which was the first attempt to tabulate the British fossils; a labour since so ably carried out by

1 Prof. Owen, in Palæontographical Society's Trans., 1849. Pl. XXI. 2 The father of Mr. S. P. Woodward of the British Museum, one of the Curators of the Paleontological department.

Mr. Morris; the frontispiece of that volume represents a fine carapace in the Norwich Museum.1

Mr. Woodward states that the buckler or shell of this Chelonian reptile often forms the nuclei of the septaria or cement-stones which occur in the eocene clay of the Norfolk coast; the one figured was dredged up from the Stour Ridge, which lies four miles out at sea from Harwich Harbour; it is 22 inches long and 18 wide. Specimens of the convex or outer surface of the carapace are less common than those that expose the interior.

This Turtle was figured and described by Mr. Konig, under the name of Testudo plana in the Icones Sectiles, fig. 192; and Prof. Owen has figured the Museum specimen (which is 13 inches long, and 10 inches wide), in his " Monograph on the Fossil Reptilia of the London Clay," Pl. XI. and XII., as Chelone crassicostata; a name derived from the great thickness of the ribs which is peculiar to this species; but it appears to me improper to expunge the specific name of a fossil that has been figured and described by an original observer, with sufficient clearness to enable the species to be identified. In every department of natural history unnecessary changes in nomenclature are most serious impediments to the advancement of scientific knowledge.

CHELONIA Breviceps.-("Pictorial Atlas," Pl. LXIX. fig. 2, 3.)-A nearly perfect cranium of a marine turtle from the Isle of Sheppey, named Emys Parkinsonii by Mr. Gray, and Chelone breviceps (short-skull) by Professor Owen, is placed in this Case: it approaches in form the recent C. mydas. In Mr. Bowerbank's collection there is a cranium of the same species, attached to the carapace and plastron: it is a small turtle, about seven and a half inches long.2

In the late Mr. Dixon's collection (now added to the National Museum) there were several species of eocene turtles, which are figured and described in his work; as, for example, C. declivis, C. trigoniceps, &c.; but these interesting fossils are not at present exposed to view.

FOSSIL TURTLES OF THE WEALDEN.- Wall-case A. B.

1" Synoptical Table of British Organic Remains;" by Samuel Woodward: Norwich, 1830.

2 Figured in "Palæontographical Monograph," 1849, Pl. I. II.

("Fossils of Tilgate Forest," 1827, Pl. VI. and VII.)—Waterworn comminuted bones and costal plates of Chelonian reptiles, are abundant in the Wealden deposits of the Isle of Purbeck, and Isle of Wight, and in the clays and sandstones of the Weald of Sussex. Their occurrence in the Purbeck beds was made known by Mr. Webster; and in the Wealden, by my early gleanings from the strata of Tilgate Forest.

With the increase of collectors, and activity of research, that followed the publication of my works on the Fossils of Sussex, remains of Chelonians of considerable interest were brought to light; but with the exception of a few almost perfect examples of the carapace and plastron from near Swanage, and considerable detached portions of the same parts from the Hastings beds of Sussex, I am not aware that more instructive relics have been discovered than those in the Case before us, which were collected by me nearly thirty years ago.1

In my "Fossils of Tilgate Forest," (published in 1827,) Pl. VI. and VII.,' are figured costal-plates of the carapace, portions of the plastron, and of the scapular arch, which are referable to three distinct groups of Chelonians.

CHELONIA Bellii.-("Medals of Creation," p. 776)-Ribs and portions of the marginal border of the carapace, and plates of the plastron, with a smooth outer surface, referable to a large species of marine turtle, were among the first vestiges of Chelonians obtained from the quarries near Cuckfield in 1820. Some of these indicate a total length of three feet. The most remarkable character in the inconsiderable portions of the skeletons of this extinct reptile that have come under my examination, is the narrow dimensions to which the intercostal spaces are reduced, from the ossification and confluence of the ribs extending to within a short distance of their distal extremities. Professor Owen states that in the convexity of the under side of the vertebral ribs,

1 Notice of the occurrence of three kinds of Chelonians in the strata of Tilgate Forest, is given in my "Fossils of the South Downs,” (p. 47) published in 1822; and of Mr. Lyell's recognition of their analogy to specimens from Stonesfield.

2 With the exception of fig. 8, Pl. V., which later discoveries have proved to belong to a Crocodilian and not to a Chelonian reptile.

and in the modifications of the form of the episternal, hyosternal, and hyposternal bones, this species offers the nearest

LIGN. 33.-DISTAL EXTREMITY OF THE RIB OF A TURTLE. TILGATE FOREST.

(CHELONIA BELLII.')

a. Apical extremity of a rib.

b. Distal portion of a coștal plate.

resemblance to the Chelone planimentum of the Harwich eocene clay.

EMYDIANS, or Freshwater Turtles, (Platemys Mantelli.)Wall-case A-B.-Of this group of Chelonians, in which the carapace is much flatter than in the land or marine Turtles, there are the remains of a species which Baron Cuvier (to whom I transmitted specimens in 1820) supposed to be identical with one discovered in the Jura limestone at Soleure by M. Hugi, and described in "Ossemens Fossiles," tome v. p. 232. The proportions of the fragments discovered indicate the breadth of the carapace to have exceeded twenty inches. A fine plate of the plastron, the left hyposternal,"

1 Named in honour of the eminent zoologist, Thomas Bell, Esq. Secretary of the Royal Society.

2 Marked No. 2338 on the specimen, and labelled in my museum, "Sternal plate of a Marine Turtle," belongs to this species, according to the observations of Professor Owen.

in Tilgate grit, is placed with the Wealden Chelonian remains in this case.

LIGN. 34.-COSTAL PLATE OF A FRESHWATER TURTLE. TILGATE FOREST. (TRETOSTERNUM BAKEWELLI.) (nat. size.)

TRETOSTERNUM (Trionyx Bakewelli.')-The most numerous, and at the same time the most enigmatical remains of Chelonians, obtained in my earliest researches in the Wealden of Sussex, were fragments of very flat costal plates of the carapace of a species of freshwater turtle, having a granulated external surface, and resembling in this respect the bony case of the recent fluviatile sub-genus, named Trionyx, from their having but three free toes on each foot. These Chelonians are distinguished by the intercostal spaces, the ribs not being ossified throughout, and their extremities having no osseous border of support; the external surface of the carapace is covered with delicate pits or hollows, for the attachment of the soft skin, which is the only dermal integument; for the animals of this genus are destitute of scutes, and consequently the dorsal and costal plates of the carapace do not exhibit furrows or grooves, produced by the margins of the scales of tortoise-shell, as in the other sub-genera.

Such are the characters of the recent turtles, whose cara

1 Notice of the occurrence of this Turtle in the Wealden was first given in my "Geol. of Sussex," 1822; it was figured and described in "Foss. Tilgate Forest," in 1827; and again, as T. Bakewelli, in "Geol. S. E. of England," 1833.