and fragile, as to render it extremely improbable that they could have sustained such an instrument of flight as the powerful wing of the Albatross; their tenuity is indeed such as to suggest their adaptation to support an expanded membrane rather than pinions.1

I have recently collected from the Wealden strata of Tilgate Forest some fragments of very large cylindrical bones, the walls of which are extremely thin, and unquestionably belong to Pterodactyles.

In concluding these notes on the flying Reptiles, I may add that Mr. Bowerbank has procured from the Kentish chalk, portions of jaws with teeth, more colossal than any previously known: some portions of the upper maxilla prove the total length of the head to have been upwards of sixteen inches; and the bones of the anterior extremity indicate a width of from sixteen to eighteen feet, from the extremity of one wing to the other!

The Mosasaurus, or Fossil Reptile of Maestricht.—Wallcase B.-Maestricht, a large city in the interior of the Netherlands, situated in the valley of the Meuse, stands on a series of calcareous arenaceous deposits belonging to the Upper Chalk, and which gradually pass below into the pure white chalk with bands of siliceous nodules. Extensive quarries have for many centuries been worked in the sandstone, especially in the eminence called St. Peter's Mountain, which is a cape or headland between the Meuse and the Jaar, formed by the termination of a range of hills that bounds the western extremity of the river valley. The mountain commences at the distance of a mile south of the city, and extends in a direction towards Liege for about three leagues; it presents an almost perpendicular escarpment towards the Meuse.

The calcareous freestone, which is extensively quarried, is soft and easily cut when first removed, but dries and hardens by exposure to the air; the total thickness of the strata is above five hundred feet.

1 A new part of the“ Palæontographical Monographs" has just appeared; in which, commenting on this idea, Professor Owen states that the wings of the Pterodactyles were composed of leather! Start not, gentle reader!-here are the very words. "It was reserved for the Author of the 'Wonders of Geology' to prefer the leathern wings of the Bat and the Pterodactyle as the lighter form."-Prof. Owen," Pal. Mon." 1851.

From the extensive works that have so long been carried on, immense quantities of stone have been removed, and the centre of the mountain is traversed by galleries, and hollowed by vast excavations. Innumerable marine shells, corals, and crustaceans, bones and teeth of fishes, and remains of turtles, are imbedded in this sandstone, and as the friable character of the rock admits of the easy extrication of the fossils, they are obtained in great perfection.'

But the organic remains for which the strata of St. Peter's Mountain are most celebrated, are the bones and teeth of an

LIGN. 43. REMAINS OF THE JAWS OF THE FOSSIL REPTILE OF MAESTRICHT. (Mosasaurus Hoffmanni.)'

enormous lizard, to which our eminent countryman, the Rev. W. D. Conybeare, gave the name of Mosasaurus, or Lizard of the Meuse.

The discovery of some remains of this animal had in the middle of the last century drawn the attention of naturalists to these quarries, and in 1770 M. Hoffman, the military surgeon attached to the Fort, who had long been an assiduous collector

1 See "Wonders of Geology," p. 309.

of the fossils of the vicinity, had the good fortune to obtain a specimen which has conferred an enduring celebrity on his

name.

Some workmen, on blasting the rock in one of the caverns of the interior of the mountain, perceived to their astonishment the jaws of a large animal attached to the roof of the chasm. The discovery was immediately made known to M. Hoffman, who repaired to the spot, and for weeks presided over the arduous task of separating the mass of stone containing these remains, from the surrounding rock. His labours were rewarded by the successful extrication of the specimen, which he conveyed in triumph to his house. This extraordinary discovery, however, soon became the subject of general conversation, and excited so much interest, that the Canon of the cathedral which stands on the mountain resolved to claim the fossil, in right of being lord of the manor; and succeeded, after a long and harassing lawsuit, in obtaining this precious relic. It remained for years in his possession, and Hoffman died without regaining his treasure, or receiving any compensation. At length the French Revolution broke out, and the armies of the Republic advanced to the gates of Maestricht. The town was bombarded; but at the suggestion of the committee of savans who accompanied the French troops to select their share of the plunder, the artillery was not suffered to play on that part of the city in which the celebrated fossil was known to be preserved. In the mean time, the Canon of St. Peter's, shrewdly suspecting the reason why such peculiar favour was shown to his residence, removed the specimen, and concealed it in a vault; but when the city was taken, the French authorities compelled him to give up his ill-gotten prize, which was immediately transmitted to the Jardin des Plantes, at Paris, where it still forms one of the most striking objects in that magnificent collection.'

The beautiful model in Case B, is a faithful representation

1 Faujas St. Fond, from whose beautiful work on the Fossils of St. Peter's Mountain (Histoire Naturelle de la Montagne de St. Pierre) the above account is taken, observes with much sang froid—“La Justice, quoique tardive, arrive enfin avec le temps." The reader will probably think that although the reverend Canon was justly despoiled of his illgotten treasure, the French Commissioners were but very equivocal representatives of Justice!

of the original, and was presented to me by Baron Cuvier in 1825. It is four and a half feet in length, and two and a half in width. It consists of both jaws, with numerous teeth, (the pterygoids bearing teeth as in the Iguanas,) and the os quadratum; and there are likewise fragments of costal processes, and one of the metatarsal or metacarpal bones : two of the large echinoderms that abound in the Maestricht deposits are imbedded in the block. The parts preserved in this celebrated specimen are the following:

The superior maxillary, or jaw-bone, of the right side, with eleven teeth; seen on its inner aspect.

The anterior part of the upper maxillary bone of the left side, which is displaced, and lies across the posterior part of the left ramus of the lower jaw.

The right pterygoid, with eight teeth.

The left pterygoid; all the teeth are wanting.

The premandibular part of the left ramus of the lower jaw, with fourteen teeth, seen on its outer aspect: a row of ten or twelve vascular foramina runs parallel with the alveolar ridge.

The right ramus of the lower jaw, with the teeth, seen on the inner aspect; the posterior part is somewhat concealed by the palatine bones. The left os quadratum, or tympanic bone, lying above the concave articular facet of the lower jaw.1

The crown of the tooth of the Mosasaurus is of a pyramidal form, slightly recurved backwards, with a smooth coat of enamel; the largest is from 23 to 3 inches in length. The tooth expands at the base into a large conical mound or root (1 inch in diameter), which is anchylosed to the summit of the alveolar ridge; a mode of implantation that is termed acrodont. The outer face of the crown is very slightly convex, and separated by two sharp crests from the inner, which is semi-conical. The pulp cavity is generally found open in the centre of the base of the crown; and the germ of the successional tooth appears on the inner side of the expanded base. The teeth of the pterygoid bones are symmetrical, their transverse section being elliptical.

Part of a lower Jaw of Mosasaurus.-On the ledge over the specimen above described is placed a very fine example

1 For details, consult "Ossemens Fossiles," tome v. p. 319. I cannot explain why the tympanic bone, which is so striking an object in the model, is omitted in the figures of Faujas St. Fond, Cuvier, &c. and in the hundred engravings of this fossil that have since appeared.

of the premandibular part of the lower jaw, with fifteen teeth, seven of which have the enamelled crowns perfect. Near it there is a fragment of another jaw with three mature teeth, and the germs of as many successional ones. These valuable fossils were presented to the British Museum by the distinguished Dr. Peter Camper in 1784.

Vertebræ of Mosasaurus.-The only other parts of the skeleton of the Maestricht reptile in the collection, are a few vertebræ placed in the recess above the Geosaurus (ante p. 153), which exemplify the general character of the spinal column; they present the ordinary structure of the vertebræ in the existing lizards and crocodiles, the body being concave in front and convex behind, and the neural arch united to the centrum by suture.

The entire vertebral column appears to have consisted of 131 vertebræ, of which 97 belonged to the tail. The structure of these elements of the spine is minutely described, and their homologies considered, in the classic work on the fossil vertebrata, to which the collector who may obtain any specimens of this kind should refer.1

The peculiar character of the posterior caudal vertebræ requires, however, a brief notice, in consequence of the interesting discovery which I had the good fortune to make in 1820, of the occurrence of remains of this genus in another division of the cretaceous

The

formation, and far from the only locality previously known. posterior caudal vertebræ of the Mosasaurus differ from the anterior by the want of transverse processes; these form a large proportion of the tail. Their faces are elliptical, at first transverse, and then more

LIGN. 44.

(nat. size.)

and more compressed at the sides. Two CAUDAL VERTEBRE OF THE A great number are destitute of chevron bones, and in many this apophysis is not articulated to the body, but soldered to it, so as to form a part of the bone itself; and it is attached,

1" Ossemens Fossiles," tome v. pp. 326-334.