The orders of Ornithosaurians may be established hereafter. Under the name Pterosauria, Prof. Owen founded one order which has for its type the Pterodactylus longirostris.

Von Meyer proposed to separate this order into two groups, one with two phalanges in the wing-finger, of which Ornithopterus is the only example, forming his Diathri; while the other group, Tetrathri, or those "with four fingers, comprised all other Pterosaurians. The Tetrathri he again subdivided, following out, as he states, the suggestion of Munster and Goldfuss, into Dentirostres or such Pterodactyles as have the jaws furnished with teeth to their anterior termination; and the Subulirostres, or such as want teeth at the extremities of the jaws. To the former group he left the name Pterodactylus, and to the latter was given the name Rhamphorhynchus. Von Meyer says that he might easily have made a few more species, as will be evident to those who inspect his plates, but he "believes that the students of living animals go too far in their tendency to subdivide:" a fancy that, if indulged in by PalÆontologists, would have the effect of restoring the old LinnÆan groups; and a complaint which, although often heard, has usually come from those who do not readily discern and appraise classificational characters. In PalÆontology genera are sometimes co-extensive with orders, while species often mean genera. It may be wearisome to the collector to be lured on to follow the devious ways of a science, but PalÆontology, the source whence the mysteries of existing nature must unravel their meaning, is the handmaid of all nature's truths which have been buried in evolving the existing creation; and a duty devolves upon PalÆontologists to make the past an inseparable part of the present, by applying to the two the same scientific method.

A year previous to the formation of Owen's Pterosauria, Bonaparte named the Order Ornithosaurii, and divided it into a family—PterodactylÆ, and a sub-family PterodactylinÆ.

Fitzinger (Systema Reptilium, 1843) also used the same ordinal name, and recognized three genera—

Pachyrhamphus, of which the type is Pterodactylus crassirostris (Gold.).

Pterodactylus, with the type P. longirostris (Cuv.).

And Ornithocephalus, with the type O. brevirostris (SÖmm.).

These and other attempts at classification all endeavour to subdivide Ornithosaurians by the head or by the tail. Other characters for primary divisions may be obtained from the pelvis.

In the majority of German Pterodactyles the ilium extends for a long distance in front of the os pubis, and only for a very short distance behind the large ischium; and the small pubis from its anterior margin gives attachment to a large prepubic bone, which resembles in form the os pubis of the Crocodile[Z], and is unlike that of the Monotreme. These appear to include the long-legged animals with short tails, at present called Pterodactyles, and form a well-marked family or order.

Another kind of pelvis is that in which the ilium extends a short way in front of the acetabulum, in which the pelvic bones inclose a much larger space. These include the Cambridge Ornithosaurians, the Rhamphorhynchus, and the Dimorphodon, and form another well-marked family.

These long-tailed Pterodactyles subdivide into three sub-families—RhamphorhynchÆ, DimorphodontÆ, and OrnithocheirÆ. The four families may then be defined thus:

In the PterodactylÆ the genera are—

In the RhamphorhynchÆ at present there appears to be but one genus known:

In the DimorphodontÆ the only genus is

In the OrnithocheirÆ the genus is

With the osteological illustrations of the Ornithosauria are arranged some premaxillary bones, which show varieties of form of the snout. These variations of shape serve easily to indicate different species. And the following memoranda from those specimens and other specimens in the drawers form a synopsis of the species of the Cambridge genera, which may hereafter be fully elucidated from the copious materials in the series of associated remains.

I.

The fragment is 2⁷/₈ths inches long, with the elliptical teeth opposite to each other, 6 on a side on the palate, and one pair in front. The first three teeth are large; behind these the teeth are about half the size. The palate is gently convex, with a faint median ridge, and measures from side to side over the fourth and subsequent sockets ¹³/₁₆ths of an inch. The height of the jaw at the fourth socket 1¹/₄ inch. The sides converge to an acute rounded rostral keel. The jaws appear to have been long. The anterior termination is vascular.

The rostral keel figured by Owen Pl. I, fig. 1 d, in the 1st Supt. Cret. Reptiles, is not square as represented there, but rounded; the sides converge more acutely, and at the ridge the keel is not half so wide as the figure makes it. The enormous size of the third tooth-socket is partly due to the cracked bone having absorbed more phosphate of lime than it could hold, and extended the cracks to fissures. The type specimen shows that there was another pair of sockets in front of, but quite close to, those which appear to terminate the lower jaw.

II.

A portion of a premaxillary bone fractured at both ends, and two inches long, corresponds with Dr Bowerbank's fossil figured Pl. XXVII. fig. 1, 3, 4, in the PalÆontographical volume for 1851. The palate is just as wide; the median ridge, the same; the teeth the same in shape and as far apart. The jaw is of the same depth, but does not deepen so rapidly behind. The only other difference is that the sockets of the teeth are less prominent on the sides, and appear to look more directly down.

The ridge in which the converging sides meet is well rounded in a dentary bone which may have pertained to this species. In the space of two inches and a quarter are 5 teeth, the posterior four extending over two inches, the other pair being in front. The palatal surface is ³/₄ of an inch broad behind the third tooth, and rather more than ⁵/₈ of an inch broad behind the fourth tooth. The length of the 4th or of the 5th sockets is two-thirds that of the second or third. In front of the 5th tooth, the jaw is an inch deep, and it tapers in a curve to the anterior end. The teeth behind the third have interspaces greater than the length of the sockets; that between the 4th and 5th being ³/₈ of an inch, while the socket only measures a quarter of an inch long. Behind the 2nd socket commences the palatal groove, broad in fronts but narrowing behind; and its sides instead of diverging as in the type, are concave so as to form a channel like a straightened Siliquaria shell. The halves of the palate bevel off so as to make a right angle with each other, and greater angles with the flat sides.

III.

Dentary bone. Broken at both ends, and wanting all its teeth, this interesting fossil shows the suture where its whole length rests on the angular bone which almost reached to the termination of the beak, quite unlike what is seen in any German Pterodactyle.

It is a narrow mandible, less than three quarters of an inch wide, with the alveolar margins parallel. The palatal surface 1¹/₂ inch long, is divided into 3 equal strips; the middle one being a deep glossal groove, slightly narrowing in front, and deepening behind, made by two inclined flat surfaces. The lateral strips are horizontal behind, and in front slope a little outward. The tooth-sockets are oval, directed outward, and as long as the interspaces, though these seem to get longer behind. In an inch and a quarter there are four teeth. Below the teeth, the sides of the jaw are compressed: though nearly parallel at the hinder fracture, the flattened surfaces approximate in front till they meet in a sharp keel, which appears to make an acute angle of about 45° with the palate; and below, where the jaw is an inch deep extends for half an inch in front of the suture with the angular bone: this suture is straight and irregularly concave, and in an inch and a quarter approximates to within ⁵/₈ths of an inch of the palate.

IV.

Middle part of a premaxillary bone fractured behind and in front, slightly distorted by compression; it is 2¹/₈th inches long, and nearly resembles O. compressirostris (Owen). The palate is about ¹/₂ an inch wide in front, and ⁵/₈ths of an inch wide behind; it is compressed mesially into a strong angular keel, between which and the teeth there is a shallow groove on each side. The groove dies away behind, and the converging parts of the keel occupy the whole space between the teeth. The teeth-sockets are small, elliptical, not opposite to each other, and placed along a distinct flattened tooth area, which looks downward and outward and separates the palate from the side of the jaw. The first pair of sockets preserved are almost ³/₁₆ths of an inch long and ¹/₁₆th of an inch wide. The interspace between that tooth and the next tooth behind is ⁷/₁₆ of an inch. Separated by similar interspaces, behind these on one side are two sockets, and on the other side one socket. The sides are flattened in front, and convex behind, (making the section of the jaw lanceolate); they are compressed and round into a narrow rostral keel. The height from the palatal ridge to the rostral keel in front is ¹¹/₁₆ths of an inch; behind it is fractured, but the height was probably ¹⁴/₁₆ths of an inch.

The palatal keel, distance of the teeth, and proportions of the jaw, distinguish it from O. compressirostris (Owen).

V.

The small piece of premaxillary on which this species is founded indicates a small animal, and nearly resembles the jaw of O. microdon.

It is scarcely an inch long; nearly ⁹/₁₆ths inch high behind, and nearly ⁷/₁₆ths of an inch high in front, so that it tapers very rapidly, and could scarcely have been an inch longer in front.

The nose is well rounded, but the sides are a little concave, and become well pinched in in the middle, behind, showing the near approach as I think to the nostril.

The palate half an inch broad, is divided into two concave channels by the strong and sharp median ridge, which projects below the alveolar margins. The dental margins are not rounded as in C. microdon, but flattened, making more than a right angle with both the outer side-wall and palate. The interspaces between the teeth are rough, looking as though they had supported minute teeth. The alveolar margin is a tenth of an inch wide; along it are the perfectly circular sockets, a sixteenth of an inch in diameter. There are 3 sockets between ⁵/₈ of an inch, so that they are separated by 3 times their diameter. The palate is obliquely impressed with blood-vessels running forward to the teeth from the median ridge.

The points in which this jaw differs from that of O. microdon are that in this species the teeth are circular instead of being oval; that the interspaces here are as long as in that species, though this jaw is only two-thirds the width; that instead of having a sharp keel on the upper surface, this has a well rounded roof. That though the jaw is scarcely higher than it is wide, it shows strong furrows running up to the nares, while in O. microdon, though the proportions are the same, the sides are perfectly flat without trace of pinching in, while the line of the nasal opening is indicated by a faint furrow running all along the jaw. And lastly it differs in size, which, where the sutures are lost, may be important in discriminating forms.

VI.

Premaxillary bone. The fossil is nearly 1³/₄ths inch long, and at the proximal end, where it is less than ³/₄ths of an inch high, has flat sides, which converge to form a keel which is depressed anteriorly and rounded so that where fractured in front the bone is ⁷/₁₆ths of an inch deep. The palatal surface contains two wide concave channels, between which descends a sharp median ridge, which behind becomes more prominent than the alveolar border.

The palate is ⁵/₈ths of an inch wide. The alveolar margins are compressed and rounded. The small tooth-sockets are oval, and four are contained in 1¹/₈th inch; they look downward.

There is a small tip of a jaw associated with this fossil, which is so like that it might be part of the bone broken off before fossilization. It corresponds in every way except that the teeth are closer. In this terminal lanceolate fragment there are in ⁵/₈ths of an inch four teeth. The snout is terminated by two, which are close together.

VII.

Ornithocheirus Huxleyi (Seeley).

The only specimen of this species yet known is the greater part of a dentary bone contained in the Museum of the Geological Survey. An inch and ¹/₄ long and ³/₄ths of an inch wide, it is less than half an inch deep: the sides slowly converge towards the front, and it appears to have had an obtusely lanceolate beak. The under surface is convex, too inflated for trace of a keel, and tapers to the end of the beak, which, with the left alveolar margin is abraded. The palatal surface is smooth at its front end, but two diverging ridges soon arise and form the boundary of a posteriorly deepening mesial channel, which is a quarter of an inch wide at the fracture. These ridges too, which are parallel with the compressed and rounded alveolar margins, convert the lateral spaces into shallow channels. The right side shows the sockets of 3 small oval teeth separated by interspaces wider than teeth. A tooth and two interspaces measure ⁷/₁₆ths of an inch.

The only cretaceous Pterodactyle which this at all resembles is O. microdon, but the palate is wider than in that species; the sides converge towards each other more rapidly, as though it belonged to a species with a shorter snout.

I am indebted to Prof. Huxley for the opportunity of making a notice of this species.

VIII.

This well-marked species is a portion of a premaxillary bone 1¹/₄ inch long, fractured behind and in front. The palate is half an inch wide; its two halves are inclined to each other at a considerable angle, and where they meet form a more prominent keel. The tooth-sockets look more outward than downward, are nearly circular, separated by interspaces as long as the sockets; three sockets and two interspaces measure one inch. The jaw is about ⁵/₈ths of an inch high in front, and about ¹/₁₆th of an inch higher behind. The sides are flat and converge like the sides of a wedge to a sharp rostral keel.

IX.

Ornithocheirus xyphorhynchus (Seeley).

I have seen but one example of this form. It has lost much of the outer layer of bone, and shows on the sides impressions like tooth-marks from an eater of Pterodactyles. A groove which has some appearance of being due to fracture traverses each side, but the specimen is symmetrical, and has its characters in no way changed by the accident.

It is a portion of a lower jaw of a long-beaked Pterodactyle of the O. Sedgwicki type, with parallel sides, and the rounded basal ridge nearly parallel with the palate.

The fragment is two inches long, showing four large and obliquely set sockets in If inch. The tooth-sockets are on the outer two-thirds of the palate, and looked forward, upward, and outward The interspaces each measure ⁵/₁₆ths of an inch.

Each half of the palatal surface which is ⁵/₁₆ of an inch wide, inclines to the other half at a right angle, being parted by a narrow groove; the diameter of the jaw is half an inch.

The depth of the jaw is ⁵/₈ths of an inch in front, and ³/₄ths of an inch behind. The sides are flat and approximate below to a sharp keel. This species is one of many in the collection of W. Reed, Esq. of York, kindly placed in my hands for the elucidation of those in the Woodwardian Museum.

X.

The fragment is 1¹/₂ inch long, with two large elliptical tooth-sockets on each side of the flattened palate, and one pair in front. The third socket is separated from the fourth by a considerable interspace. Between the third sockets arises the median palatal ridge, and from the inner margin of each socket a lateral ridge appears to be continued. Behind the third socket the jaw measures ¹¹/₁₆ths of an inch from side to side, and ¹⁰/₁₆ths of an inch high. The sides converge and round convexly into each other. The jaws appear to have been long; It is only known by upper jaws. The type specimen shows the socket of another tooth in front of the last one figured by Prof. Owen. It is directed outward at a greater angle, and separated from the hinder one by a wall not ¹/₁₆th of an inch thick, and the teeth of this pair must have been parted from each other by a film equally thin. There is no truncation of the snout as in O. Woodwardi.

Another specimen shows some variations. This fragment of a premaxillary bone is fractured through the third pair of tooth-sockets in front and through the seventh pair behind. It is about 2¹/₈th inches long; the palate is ¹¹/₁₆ths of an inch wide behind the great tooth, and maintains the same width. The jaw is ¹¹/₁₆ths of an inch high behind, and ¹⁰/₁₆ths high in front. The sides are gently convex, and imperceptibly unite to form the well-rounded depressed mesial ridge of the beak. From the front of the third to the back of the fifth socket measures 1³/₈ths inch. The sockets are ovate, rather smaller, and closer together than in the type of O. Fittoni; margins elevated. The variations from types are so many, and often so considerable, as to suggest the idea that the fossil groups called species may in the living animals have often been genera.

In all the specimens the end of the palate is a little reflected upward.

XI.

A fragment of premaxillary bone two inches long, fractured behind the socket for the seventh tooth. It most nearly resembles O. Sedgwicki and O. Cuvieri. Behind the second tooth the palate is ¹/₂ an inch wide; behind the sixth socket it is ⁵/₈ths of an inch wide; the distance between these points is nearly 1¹/₂ inch. The palate is flattened, with a sharp slight mesial keel and a wide concave channel on each side which dies away in front. The first pair of teeth are in front of the snout, rather small, and look forward. In this specimen the large third tooth is not developed on the left side. The second and third sockets are large and close together; the succeeding teeth are parted from each other by interspaces equal to their own diameter. They are gibbously elliptical. The sides of the jaw are gently convex from above downward; they round into each other to form a narrow rostral keel. Behind the second socket the jaw is ¹/₂ an inch high; behind the sixth it is nearly ⁷/₈ths of an inch high.

The grooved and relatively wider palate, and the relatively smaller teeth, abundantly distinguish this species from O. Sedgwicki (Owen).

The smaller, more circular teeth, placed closer together, distinguish it from O. Cuvieri (Bowerbank).

XII.

This fragment of premaxillary bone is 1¹/₂ inch long. The palate is ¹/₂ an inch wide behind, and the jaw is rather more than ¹/₂ an inch high; behind the second tooth it is nearly ⁵/₈ths of an inch high. The sides converge superiorly to form a well-rounded keel. The palate is flattened, with a slightly elevated blunt median keel. There appears to be a pair of small teeth in front of the snout as usual, and six on the palate, with an indication of another at the posterior fracture. The teeth are of moderate size and almost circular. In the form of the bone it is readily distinguished from all the species enumerated.

XIII.

An ill-preserved fragment fractured in front and behind, yet indicating a distinct species. The palate is flat, with the faintest median ridge, and the sides are flat and round into a narrow rostral keel, which in front approximates rapidly towards the palate. The first pair of sockets are missing; what appears to be the second pair are about ¹/₈th of an inch long, separated from the pair behind by an interspace of ¹/₄th of an inch. These are ovate and less than ¹/₄th of an inch long, and separated from the next pair by an interspace of not less than ¹/₄th of an inch. The height of the jaw over the first pair of sockets preserved is ⁹/₁₆ths of an inch; over the second pair it is ¹⁴/₁₆ths of an inch; the space between these points is ⁹/₁₆ths of an inch. Behind the second pair of teeth the palate is nearly ⁵/₈ths of an inch wide.

The only species which it resembles is O. brachyrhinus, but differs from that in the flatter, narrower palate, which makes a greater angle with the rostral keel, and in the smaller teeth, which are separated by wider interspaces.

XIV.

A fragment of a premaxillary bone 6 inches long. It somewhat resembles O. Cuvieri in the aspect of the palate, but the jaw is more elongated, and expands from side to side at the anterior end. The teeth are opposite to each other in front, but become irregular after the sixth. The palate measures behind the second pair of sockets ³/₄ths of an inch, behind the third pair it is a sixteenth of an inch wider, behind the ninth pair half an inch, and in the last two inches it begins to widen again. A sharp keel arises behind the second pair of sockets and becomes more prominent to behind the tenth pair, when the channel which accompanies it on each side seems to disappear. The first pair of teeth, which look forward, is smaller than the second and third pairs; they are closer together than those which follow. The third sockets are ⁷/₈ths of an inch from the tip of the snout. Then follow three smaller, more circular teeth, which are separated from each other by interspaces as long as the sockets. The back of the sixth sockets are 2¹/₄ inches from the tip of the snout. Then follow two larger more elliptical sockets; after which the sockets become smaller and are separated by longer distances, that between the 10th and 11th pairs is nearly ³/₄ths of an inch.

The height of the jaw behind the second pair of sockets is ⁵/₈ths of an inch, behind the sixth sockets ¹⁵/₁₆ths, behind the tenth sockets 1¹/₄ inch. In front, the nose has the aspect of being compressed from above downward, and behind it is compressed from side to side. The sides are flattened and round into a narrow rostral ridge which is depressed at the anterior end.

XV.

This species is founded on the anterior end of a premaxillary bone; in form not unlike O. Fittoni. It is ⁵/₈ths of an inch wide; the lateral margins approximate very slowly, and in front it appears to be truncated. It is an inch and a quarter long, and in that space were on each side six large round teeth, almost as close together as they could be, five on the palate and a pair in front. The terminal two are no wider apart than the rest, and point more forward. A moderate, sharp, median ridge descends in the flattened palate, making its lateral halves a little concave. The front termination of the palate is slightly reflected upward. The jaw, which is ¹/₂ an inch deep behind, tapers to its termination more rapidly than does O. Fittoni. The flat sides similarly converge, and form a well-rounded ridge, which does not get blunter in front. From their close approximation, it results that the tooth-sockets are entirely above the palatal surface, so that they are better seen from the side of the jaw than from the palate.

It is a clearly marked species, as well distinguished from O. Fittoni by the closeness of its teeth, as O. Sedgwicki is from O. Cuvieri.

XVI.

This is a species which can only be confounded with O. polyodon. It is a fragment of premaxillary bone 1³/₄ inch long, fractured through the seventh socket. It differs from O. polyodon in having larger teeth, which are wider apart, look more downward, have a narrower palatal interspace between each pair, and a rostral keel, which is more compressed from side to side behind and from above downward in front, and makes a greater angle with the palate.

The sockets are more uniform in size and closer together than usual, the second and third pairs being but slightly larger than the others; all are broadly elliptical. The palatal keel becomes sharp and prominent behind the fourth sockets. Behind the second pair of sockets the height of the jaw is nearly ⁷/₁₆ths of an inch, behind the fourth sockets the height is ¹⁰/₁₆ths of an inch; the distance between these points is about ¹⁰/₁₆ths of an inch.

XVII.

This is a fragment of a ?premaxillary bone, fractured behind through the socket for the fourth tooth. It approximates to O. colorhinus, but differs chiefly in the nose not extending in front of the first pair of teeth; in there not being any lunate area above the first pair of teeth; in there being but one tooth in front, which is relatively large; in the socket for the fourth tooth being quite close to that for the third tooth, and in the palatal sockets looking much more outward. The nose also appears to be better rounded.

The fragment is 1⁷/₈ inch long. The second and third sockets, with their interspace, measure 1¹/₈ inch. On the opposite side the first socket is intermediate in position between the first and second.

Though not likely, it is just possible that this might be the premaxillary bone of O. eurygnathus.

XVIII.

This fragment of a premaxillaiy bone is fractured behind the sockets for the third pair of teeth. It is 1¹/₈ inch long, and shows one pair of small teeth in front and two pairs of large ovate teeth on the palate. The first pair are divided from each other and from the second pair by films of bone; and the second pair are separated from the third by rather more than half the length, of the third socket. Behind the third pair of sockets the palate is ⁵/₈ths of an inch wide; it is flattened, and has a blunt moderately elevated mesial ridge. Behind the second pair of sockets the jaw is ⁵/₈ths of an inch high; behind the third pair of sockets it is ³/₄ths of an inch high; the distance between the places of measurement is ¹/₂ an inch. The sides are flat and converge to a rounded nose. The jaw is rounded from side to side in front, and the outline of the top of the nose rounds over the blunt termination of the snout above the teeth on to the palate.

In the shortness of the nose it somewhat resembles the ?P. giganteus (Bowerbank), but the jaw attenuates less rapidly, is truncated, and has larger teeth.

XIX.

This species nearly resembles O. brachyrhinus, from which it differs in larger size, with a relatively wider palate, which is without a keel, and in a larger front pair of teeth. It approximates towards O, colorhinus, but is smaller, and wants the rugose lunate area over the front pair of teeth characteristic of that species. There are many varieties or species nearly related to this type, but from their imperfect preservation and the small part of the head which they represent, it is not possible to give descriptions of them.

XX.

A fragment of a ?dentary bone, fractured behind through the socket for the third tooth. The sockets are nearly circular. It measures about an inch long,, and behind the socket for the second tooth 1³/₄ inch high. The sides of the jaw are gently concave from above downward, having a pinched aspect and approximating; they round into a narrow rostral ridge, which widens towards the tip of the snout and is truncated by a small sub-circular [or sub-pentagonal] rugose area at right angles with the part of the palate behind the first pair of sockets. The first pair of sockets are nearly as large as the second, and from the steep incline of the jaw look more than usually upward; they are ⁷/₁₆ths of an inch long, are separated from each other by an interspace of ⁶/₁₆ ths, and from the second sockets by an interspace of more than ¹/₈th of an inch, while the second socket is separated from the third by about ¹/₄th of an inch. The palatal space between the second pair is about ³/₄ths of an inch.

XXI.

Fragments of premaxillary bones. The largest portion is 2¹/₂ inches long, and is fractured behind the socket for the fourth tooth, and the upper part of the nose is also broken away. The palate is flattened, with the median part slightly convex. The sides of the jaw converge upward, but not rapidly; in front they round into each other, but there is a slight mesial depression. The front pair of teeth are large, separated from each other and from the second pair by films of bone. Above the first pair of sockets, so as to look downward and forward, is an impressed lunate area ⁹/₁₆ths of an inch wide and ⁵/₁₆ths of an inch high, to which a soft lip may have been attached. This area is in the same plane with the first pair of teeth and at right angles with the upper outline of the nose. The sockets of the first pair of teeth are a little smaller than the second pair; they are both about half an inch in diameter and nearly circular. An interspace of ³/₁₆ths of an inch separates the second socket from the third. The tooth is elliptical, the socket being narrower and longer than that of the second. The palatal interspace between the third pair is more than ³/₄ths of an inch. The interspace between the third and fourth sockets is about ³/₈ths of an inch. The diameter of the nearly circular fourth socket is ¹/₄th of an inch.

The overhanging lunate lip space, with the size of the teeth and width of the palate, abundantly distinguish this species.

XXII.

I regard the fragment on which this species was founded as being the terminal end, and not a section of a jaw; partly from the rounding of the lateral surfaces to the front, and chiefly from the snapped off teeth in the middle of the truncated anterior end, for they are smaller than the pair behind them, and look forward at a greater angle, so that the converging sockets of both pairs meet behind. These characters are well shown in Mr Dinkel's excellent figure, Pl. II. fig. 3a. Second Sup. PalÆont. The palate is destroyed, and gives no clue to the bone being either lower or upper.

Another specimen, rather smaller, shows the rostrum well rounded; the front is truncated at right angles to it: there is the same rounding of its lower part into the sides, and the stumps of the front pair of teeth are visible though they are again worn level with the rugose front of the snout.

But the finest fragment of this species is a rostral end, (perhaps of the upper jaw) three inches long, two inches deep, and with the palate as wide. It indicates 5 teeth on a side: the front pair small, 2nd and 3rd much larger, and two pairs behind, which are smaller. The palate is flat, and attains its greatest width at the third tooth, behind which it contracts noticeably. The third tooth is more than half an inch in diameter, the fourth is ⁵/₁₆ths of an inch long. The spaces between teeth seem equal to the long diameter of the sockets, which are oval and straight. The sides round into the front of the muzzle more gradually in this specimen than in the others. An impressed line runs along the median ridge of the upper surface. Just as the jaw gets narrower behind, so the well-rounded upper surface becomes more acute behind.

Behind the third socket the palate measures 1⁷/₈ inch from side to side, and the jaw is there nearly 2 inches high.

This is the most massive Pterodactyle jaw known. In the recent state it may have indicated a creature sufficiently distinguished from those to which the smaller fossils belonged, but now the divergence of characters is so slight as to be for zoological purposes of no value.

It is related to O. Fittoni; the chief points of difference being the truncated muzzle, the compression behind the third tooth, the much sharper (?) dorsal ridge, and the large size of the head.

XXIII.

A fragment of premaxillary bone, well distinguished from every other specimen, except one in the collection of Mr Reed of York, which is here named O. Reedi. It is a large head, with larger teeth than any known species. The jaw is truncated in front, with a rugose vertical area in front reaching 1³/₄ inch high from the palate, on which the usual front pair of teeth are not seen. At the angle of this front area with the palate is a large elliptical tooth ⁹/₁₆ths of an inch wide, and behind it, with an interspace of ³/₁₆ths of an inch, is a socket measuring ¹⁰/₁₆ths of an inch in length; the next interspace is about ¹/₈th of an inch, and the next nearly circular socket is ⁵/₁₆ths long; then another interspace of ¹/₈th of an inch, and another and a smaller tooth. The palate appears to have been channelled. The sides of the jaw are flat, or slightly concave, and where fractured above, are 3 inches high. Above the rugose vertical area of the snout, is an area, concave from back to front, reaching up to the rostral keel; it is flat from side to side behind, and convex from side to side in front. So much as is preserved measures 1³/₄ inch in length, and appears to be relatively narrower than in O. Reedi.

XXIV.

Ornithocheirus Reedi (Seeley).

The anterior part of an upper jaw has flattened slightly concave sides, which converge above so as to form boundaries of (1) a flat triangular area which looks anteriorly, and of (2) an oblong area, traversed by a mesial groove, which looks upward and forward and is concave from back to front. In the lower half of the truncated triangular anterior termination are the remains of the stumps of the two anterior teeth; they are oval in outline, ⁹/₁₆ths of an inch high, and ⁷/₁₆ths of an inch wide; they are parted by an interspace nearly ¹/₄ of an inch wide, which becomes concave vertically as it rounds on to the palatal surface. All the front triangular surface above the teeth is rough: its entire height is about 1¹/₄ inch, and is nearly as wide across the base. The side rounds a little into the concave median upper surface, and into the triangular front; so much as is preserved measures 2¹/₂ inches high, and 1³/₈ inch long. The palatal surface, which is very small and badly preserved, is 1³/₄ inch wide behind, but gives no indication of further widening. On its outer border are seen two large circular teeth ⁵/₈ths of an inch in diameter; they are separated by a median palatal interspace of ⁷/₈ths of an inch. Where it is fractured behind, the specimen shows the sockets of another pair of teeth behind these, with an interspace of ¹/₄ of an inch in the antero-posterior direction. The palate is convex.

The superior oblong area is concave in length as well as transversely. It makes a great angle with the triangular front of which it is the upward continuation; so much as is preserved extends 1¹/₂ inch in length; it is about ¹/₂ an inch wide.

I am indebted to W. Reed, Esq. of York, for the opportunity of making a notice of this species, which closely resembles O. capito.

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XXV.

The palate is 2³/₄ inches long, and at the second pair of teeth about ⁷/₈ths of an inch wide. It is fractured at the end through the fifth socket, and at the side along the palatal groove. The first pair of teeth is smaller and closer together than the others. The palatal interspace between the second pair is ³/₈ths of an inch; between the third pair, which are large teeth, it is ¹/₂ an inch. The sockets are sub-circular, and are not separated from each other by wider interspaces than their own length. In front is a long triangular rugose area, convex from above downward, a distance of 1¹/₂ inch; and concave from side to side, a width above of rather more than ¹/₂ an inch. Below this the flattened sides converge to a blunt keel; where, fractured, the jaw is 2¹/₂ inches deep. There are several fragments of species allied to the last; one has the triangular area in front very small, only half as high as in the type and very narrow, for the sides are gently rounded into it. It is marked by short longitudinal furrows, impressed vessels I think, while in O. simus the surface is irregularly rough. The first pair of teeth are much larger than in O. simus; they are longer, more conical, and circular, and separated by as wide a space as the second pair. There is not much to found a species on, but as it appears to be quite distinct from O. simus, it is named O. Carteri. Another fragment, with the area very long, is marked O. platyrhinus. But a sufficiency of species has been indicated to make known the Ornithosaurian fauna of the Cambridge Greensand. And the detailed description of critical types and of the other parts of the skeletons is beyond the general osteology of the tribe, and will rather belong to a memoir in which this flock of Pterodactyles will be restored to their living forms.

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