These strange and gigantic Saurians seem almost to disappear during the succeeding geological periods; for, although they have been discovered as low down as the Trias in Germany, and as high up as the Chalk in England, they only appear as stragglers in these epochs; so, too, the Reptiles, the existing Saurians are, as it were, only the shadowy, feeble representatives of these powerful races of the ancient world.

Confining ourselves to well-established facts, we shall consider in some detail the best known of these fossil reptiles--the _Ichthyosaurus_, _Plesiosaurus_, and _Pterodactyle_.

The extraordinary creature which bears the name of _Ichthyosaurus_ (from the Greek words ????? sa????, signifying fish-lizard), presents certain dispositions and organic arrangements which are met with dispersed in certain cla.s.ses of animals now living, but they never seem to be again reunited in any single individual. It possesses, as Cuvier says, the snout of a dolphin, the head of a lizard, the jaws and teeth of a crocodile, the vertebrae of a fish, the head and sternum of a lizard, the paddles like those of a whale, and the trunk and tail of a quadruped.

Bayle appears to have furnished the best idea of the Ichthyosaurus by describing it as the Whale of the Saurians--the Cetacean of the primitive seas. It was, in fact, an animal exclusively marine; which, on sh.o.r.e, would rest motionless like an inert ma.s.s. Its whale-like paddles, and fish-like vertebrae, the length of the tail and other parts of its structure, prove that its habits were aquatic; as the remains of fishes and reptiles, and the form of its teeth, show that it was carnivorous.

Like the Whale, also, the Ichthyosaurus breathed atmospheric air; so that it was under the necessity of coming frequently to the surface of the water, like that inhabitant of the deep. We can even believe, with Bayle, that it was provided, like the Whale, with vents or blowers, through which it ejected, in columns into the air, the water it had swallowed.

The dimensions of the Ichthyosaurus varied with the species, of which five are known and described. These are _Ichthyosaurus communis_, _I.

platydon_, _I. intermedius_, _I. tenuirostris_, and _I. Cuvierii_, the largest being more than thirty feet in length.

[Ill.u.s.tration: Fig. 96.--Ichthyosaurus platydon.]

[Ill.u.s.tration: Fig. 97.--Lower jaw of Ichthyosaurus. (Dr. Buckland.)]

[Ill.u.s.tration: Fig. 98.--Skeleton of Ichthyosaurus.

Containing teeth and bones of Fishes in a coprolitic form. One-fifteenth natural size.]

The short, thick neck of the Ichthyosaurus supported a capacious head, and was continued backwards, from behind the eyes, in a column composed of more than a hundred vertebrae. The animal being adapted, like the whale, for rapid movement through the water, its vertebrae had none of the invariable solidity of those of the Lizard or Crocodile, but rather the structure and lightness of those of Fishes. The section of these vertebrae presents two hollow cones, connected only by their summits to the centre of the vertebrae, which would permit of the utmost flexibility of movement. The ribs extended along the entire length of the vertebral column, from the head to the pelvis. The bones of the sternum, or that part of the frame which supported the paddles, present the same combinations with those of the sternum in the Ornithorhynchus, or Duck-billed Platypus, of New Holland, an animal which presents the singular combination of a mammalian furred quadruped having the bill of a duck and webbed feet; which dived to the bottom of the water in search of its food, and returned to the surface to breathe the air. In this phenomenon of living Nature the Creator seems to have repeated, in our days, the organic arrangements which he had originally provided for the Ichthyosaurus.

In order that the animal should be able to move with rapidity in the water, both its anterior and posterior members were converted into fins or paddles. The anterior fins were half as large again as the posterior.

In some species each paddle was made up of nearly a hundred bones, of polygonal form, and disposed in series representing the phalanges of the fingers. This hand, jointed at the arm, bears resemblance, in osteological construction, to the paddles, without distinct fingers, of the Porpoise and the Whale. A specimen of the posterior fin of _I.

communis_, discovered at Barrow-on-Soar, in Leicestershire, in 1840, by Sir Philip Egerton, exhibited on its posterior margin the remains of cartilaginous rays, which bifurcated as they approached the edge, like those in the fins of a fish. "It had previously been supposed," says Professor Owen, "that the locomotive organs were enveloped, while living, in a smooth integument, like that of the turtle and porpoise, which has no other support than is afforded by the bones and ligaments within; but it now appears that the fin was much larger, expanding far beyond the osseous frame-work, and deviating widely in its fish-like rays from the ordinary reptilian type." The Professor believes that, besides the fore-paddles, these stiff-necked Saurians were furnished at the end of the tail with a fin to a.s.sist them in turning, not placed horizontally, as in the whale, but vertically, forming a powerful instrument of progression and motion. It is obvious that the Ichthyosaurus was an animal powerfully armed for offence and defence. We cannot say, with certainty, whether the skin was smooth, like that of the whale or lizard, or covered with scales, like the great reptiles of our own age. Nevertheless, as the scales of the Fishes and the cuira.s.s and h.o.r.n.y armour of other Reptiles of the Lias are preserved, and as no such defensive scales have been found belonging to the Ichthyosaurus, it is probable that the skin was naked and smooth. The tail, composed of from eighty to eighty-five vertebrae, was provided with large and long paddles, arranged vertically as in the Whale.

It is curious to see to what a degree of perfection has been carried, in our days, the knowledge of the antediluvian animals, their habits, and their economy. Fig. 98 represents the skeleton of an Ichthyosaurus found in the Lias of Lyme Regis, which still retains in its abdominal cavity coprolites, that is to say, the residue of digestion. The soft parts of the intestinal ca.n.a.l have disappeared, but the _faeces_ themselves are preserved, and their examination informs us as to the alimentary regimen of this animal which has perished from the earth many thousands, perhaps millions, of years. Mary Anning, to whom we owe many of the discoveries made in the neighbourhood of Lyme Regis, her native place, had in her collection an enormous coprolite of the Ichthyosaurus. This coprolite (Fig. 99) contained some bones and scales of Fishes, and of divers Reptiles, well enough preserved to have their species identified.

It only remains to be added that, among the bones, those of the Ichthyosaurus were often found, especially those of young individuals.

The presence of the undigested remains of vertebrae and other bones of animals of its own species in the coprolites of the Ichthyosaurus proves, as we have already had occasion to remark, that this great Saurian must have been a most voracious monster, since it habitually devoured not only fish, but individuals of its own race--the smaller becoming the prey of the larger. The structure of the jaw of the Ichthyosaurus leads us to believe that the animal swallowed its prey without dividing it. Its stomach and intestines must, then, have formed a sort of pouch of great volume, filling entirely the abdominal cavity, and corresponding in extent to the great development of the teeth and jaws.

[Ill.u.s.tration: Fig. 99.--Coprolite, enclosing bones of small Ichthyosaurus.]

[Ill.u.s.tration: Fig. 100.--Coprolite of Ichthyosaurus.]

The perfection with which its contents have been preserved in the fossilised coprolites, furnishes indirect proofs that the intestinal ca.n.a.l of the Ichthyosaurus resembled closely that of the shark and the dog-fish--fishes essentially voracious and destructive, which have the intestinal ca.n.a.l spirally convoluted, an arrangement which is exactly that indicated in some of the coprolites of the Ichthyosaurus, as is evident from the impressions which the folds of the intestine have left on the coprolite, of which Fig. 100 is a representation. In the cliffs near Lyme Regis coprolites are abundant in the Lia.s.sic formation, and have been found disseminated through the shales and limestones along many miles of that coast.

What an admirable privilege of science, which is able, by an examination of the simplest parts in the organisation of beings which lived ages ago, to give to our minds such solid teachings and such true enjoyments!

"When we discover," says Dr. Buckland, "in the body of an Ichthyosaurus the food which it has engulfed an instant before its death, when the intervals between its sides present themselves still filled with the remains of fishes which it had swallowed some ten thousand years ago, or a time even twice as great, all these immense intervals vanish, time disappears, and we find ourselves, so to speak, thrown into immediate contact with events which took place in epochs immeasurably distant, as if we occupied ourselves with the affairs of the previous day."

[Ill.u.s.tration: Fig. 101.--Skull of Plesiosaurus restored. (Conybeare.)

_a_, profile; _b_, seen from above.]

The name of _Plesiosaurus_ (from the Greek words p??s???, _near_, and sa????, _lizard_) reminds us that this animal, though presenting many peculiarities of general structure, is allied by its organisation to the Saurian or Lizard family, and, consequently, to the Ichthyosaurus.

The Plesiosaurus presents, in its organic structure, the most curious a.s.semblage we have met with among the organic vestiges of the ancient world. The Plesiosaurus was a marine, air-breathing, carnivorous reptile, combining the characters of the head of a Lizard, the teeth of a Crocodile, a neck of excessive length resembling that of a Swan, the ribs of a Chameleon, a body of moderate size, and a very short tail, and, finally, four paddles resembling those of a Whale. Let us bestow a glance upon the remains of this strange animal which the earth has revealed, and which science has restored to us.

The head of the Plesiosaurus presents a combination of the characters belonging to the Ichthyosaurus, the Crocodile, and the Lizard. Its enormously long neck comprises a greater number of vertebrae than the neck of either the Camel, the Giraffe, or even the Swan, which of all the feathered race has the longest neck in comparison to the rest of the body. And it is to be remarked, that, contrary to what obtains in the Mammals, where the vertebrae of the neck are always seven, the vertebrae in birds increase in number with the length of the neck.

[Ill.u.s.tration: Fig. 102.--Skeleton of Plesiosaurus dolichodeirus restored. (Conybeare princ.i.p.ally.)]

The body is cylindrical and rounded, like that of the great marine Turtles. It was, doubtless, naked, _i.e._, not protected with the scales or carapace with which some authors have invested it; for no traces of such coverings have been found near any of the skeletons which have been hitherto discovered. The dorsal vertebrae are attached to each other by nearly plane surfaces like those of terrestrial quadrupeds, a mode of arrangement which must have deprived the whole of its vertebral column of much of its flexibility. Each pair of ribs surrounded the body with a complete girdle, formed of five pieces, as in the Chameleon and Iguana; whence, no doubt, as with the Chameleon, great facilities existed for the contraction and dilatation of the lungs.

[Ill.u.s.tration: Fig. 103.--Sternum and pelvis of Plesiosaurus. Pub., pubis; Isch., ischium; Il., ilium.]

The breast, the pelvis, and the bones of the anterior and posterior extremities furnished an apparatus which permitted the Plesiosaurus, like the Ichthyosaurus and existing Cetaceans, to sink in the water and return to the surface at pleasure (Fig. 103). Prof. Owen, in his "Report on British Reptiles," characterises them as air-breathing and cold-blooded animals; the proof that they respired atmospheric air immediately, being found in the position and structure of the nasal pa.s.sages, and the bony mechanism of the thoracic duct and abdominal cavity. In the first, the size and position of the external nostrils (Fig. 102), combined with the structure of the paddles, indicate a striking a.n.a.logy between the extinct Saurians and the Cetaceans, offering, as the Professor observes, "a beautiful example of the adaptation of structure to the peculiar exigencies of species." While the evidence that they were cold-blooded animals is found in the flexible or unanchylosed condition of the osseous pieces of the occiput and other cranial bones of the lower jaw, and of the vertebral column; from which the Professor draws the conclusion that the heart was adapted for transmitting a part only of the blood through the respiratory organs; the absence of the ball-and-socket articulations of the bones of the vertebrae, the position of the nostrils near the summit of the head, the numerous short and flat digital bones, which must have been enveloped in a simple undivided integumentary sheath, forming in both fore and hind extremities a paddle closely resembling that of the living Cetacea. The paddles are larger and more powerful than those of the Ichthyosaurus, to compensate for the slight a.s.sistance the animal derived from the tail. The latter--shorter, as compared with the length of the rest of the body, than in the Ichthyosaurus--was more calculated to act the part of a rudder, in directing the course of the animal through the water, than as a powerful organ of propulsion.

[Ill.u.s.tration: Fig. 104.--Remains of Plesiosaurus macrocephalus.

One-twelfth natural size.]

Such were the strange combinations of form and structure in the Plesiosaurus and Ichthyosaurus--genera of animals whose remains have, after an interment extending to unknown thousands of years, been revealed to light and submitted to examination; nay, rebuilt, bone by bone, until we have the complete skeletons before us, and the habits of the animals described, as if they had been observed in life. Conybeare thus speaks of the supposed habits of these extinct forms, which he had built up from scanty materials: "That the Plesiosaurus was aquatic is evident from the form of its paddles; that it was marine is equally so, from the remains with which it is universally a.s.sociated; that it may have occasionally visited the sh.o.r.e, the resemblance of its extremities to the turtle may lead us to conjecture; its motion, however, must have been very awkward on land; its long neck must have impeded its progress through the water, presenting a striking contrast to the organisation which so admirably fits the Ichthyosaurus for cutting through the waves.

May it not, therefore, be concluded that it swam on or near the surface, arching back its long neck like the swan, and occasionally darting it down at the fish which happened to float within its reach? It may, perhaps, have lurked in shallow water along the coasts, concealed among the sea-weeds, and, raising its nostrils to the surface from a considerable depth, may have found a secure retreat from the a.s.saults of dangerous enemies, while the length and flexibility of its neck may have compensated for the want of strength in its jaws, and incapacity for swift motion through the water, by the suddenness and agility of the attack they enabled it to make on every animal fitted to become its prey."

The Plesiosaurus was first described by the Rev. W. D. Conybeare and Sir Henry De la Beche, in the "Geological Society's Transactions" for 1821, and a restoration of _P. dolichodeirus_, the most common of these fossils, appeared in the same work for 1824. The first specimen was discovered, as the Ichthyosaurus had been previously, in the Lias of Lyme Regis; since then other individuals and species have been found in the same geological formation in various parts of England, Ireland, France, and Germany, and with such variations of structure that Professor Owen has felt himself justified in recording sixteen distinct species, of which we have represented _P. dolichodeirus_ (Fig. 102), as restored by Conybeare, and _P. macrocephalus_ (Fig. 104), with its skeleton, as moulded from the limestone of Lyme Regis, which has been placed in the Palaeontological Gallery of the British Museum.

[Ill.u.s.tration: XV.--Ideal scene of the Lias with Ichthyosaurus and Plesiosaurus.]

The Plesiosaurus was scarcely so large as the Ichthyosaurus. The specimen of _I. platydon_ in the British Museum probably belonged to an animal four-and-twenty feet long, and some are said to indicate thirty feet, while there are species of Plesiosauri measuring eighteen and twenty, the largest known specimen of _Plesiosaurus Cramptoni_ found in the lias of Yorkshire, and now in the Museum of the Royal Society of Dublin, being twenty-two feet four inches in length. On the opposite page (PLATE XV.) an attempt is made to represent these grand reptiles of the Lias in their native element, and as they lived.

Cuvier says of the Plesiosaurus, "that it presents the most monstrous a.s.semblage of characteristics that has been met with among the races of the ancient world." This expression should not be understood in a literal sense; there are no monsters in Nature; in no living creature are the laws of organisation ever positively infringed; and it is more in accordance with the general perfection of creation to see in an organisation so special, in a structure which differs so notably from that of the animals of our own days, the simple development of a type, and sometimes also the introduction of beings, and successive changes in their structure. We shall see, in examining the curious series of animals of the ancient world, that the organisation and physiological functions go on improving unceasingly, and that each of the extinct genera which preceded the appearance of man, present, for each organ, modifications which always tend towards greater perfection. The fins of the fishes of Devonian seas become the paddles of the Ichthyosauri and of the Plesiosauri; these, in their turn, become the membranous foot of the Pterodactyle, and, finally, the wing of the bird. Afterwards comes the articulated fore-foot of the terrestrial mammalia, which, after attaining remarkable perfection in the hand of the ape, becomes, finally, the arm and hand of man, an instrument of wonderful delicacy and power, belonging to an enlightened being gifted with the divine attribute of reason! Let us, then, dismiss any idea of monstrosity with regard to these antediluvian animals; let us learn, on the contrary, to recognise, with admiration, the divine proofs of design which they display, and in their organisation to see only the handiwork of the Creator.

Another strange inhabitant of the ancient world, the _Pterodactylus_ (from pte???, _a wing_, and da?t????, _a finger_), discovered in 1828, made Cuvier p.r.o.nounce it to be incontestably the most extraordinary of all the extinct animals which had come under his consideration; and such as, if we saw them restored to life, would appear most strange and dissimilar to anything that now exists. In size and general form, and in the disposition and character of its wings, this fossil genus, according to Cuvier, somewhat resembled our modern bats and vampyres, but had its beak elongated like the bill of a woodc.o.c.k, and armed with teeth like the snout of a crocodile; its vertebrae, ribs, pelvis, legs, and feet resembled those of a lizard; its three anterior fingers terminated in long hooked claws like that on the fore-finger of the bat; and over its body was a covering, neither composed of feathers as in the bird, nor of hair as in the bat, but probably a naked skin; in short, it was a monster resembling nothing that has ever been heard of upon earth, except the dragons of romance and heraldry. Moreover, it was probably noctivagous and insectivorous, and in both these points resembled the bat; but differed from it in having the most important bones in its body constructed after the manner of those of reptiles.

[Ill.u.s.tration: Fig. 105.--Pterodactylus cra.s.sirostris.]

"Thus, like Milton's fiend, all-qualified for all services and all elements, the creature was a fit companion for the kindred reptiles that swarmed in the seas, or crawled on the sh.o.r.es, of a turbulent planet:

"The Fiend, O'er bog, or steep, through strait, rough, dense, or rare, With head, hands, wings, or feet, pursues his way, And sinks, or swims, or wades, or creeps, or flies.

_Paradise Lost_, Book II., line 947.

"With flocks of such-like creatures flying in the air, and shoals of Ichthyosauri and Plesiosauri swarming in the ocean, and gigantic Crocodiles and Tortoises crawling on the sh.o.r.es of primaeval lakes and rivers--air, sea, and land must have been strangely tenanted in these early periods of our infant world."[64]

[64] Professor Buckland on the Pterodactylus. "Trans. Geol. Soc.," 2nd series, vol. iii., p. 217.

[Ill.u.s.tration: Fig. 106.--Pterodactylus brevirostris.]

The strange structure of this animal gave rise to most contradictory opinions from the earlier naturalists. One supposed it to be a bird, another a bat, and others a flying reptile. Cuvier was the first to detect the truth, and to prove, from its organisation, that the animal was a Saurian. "Behold," he says, "an animal which in its osteology, from its teeth to the end of its claws, presents all the characters of the Saurians; nor can we doubt that their characteristics existed in its integuments and softer parts, in its scales, its circulation, its generative organs: it was at the same time provided with the means of flight; but when stationary it could not have made much use of its anterior extremities, even if it did not keep them always folded as birds fold their wings. It might, it is true, use its small anterior fingers to suspend itself from the branches of trees; but when at rest it must have been generally on its hind feet, like the birds again, and like them it must have carried its neck half-erect and curved backwards, so that its enormous head should not disturb its equilibrium." This diversity of opinion need not very much surprise us after all, for, with the body and tail of an ordinary mammal, it had the form of a bird in its head and the length of its neck, of the bat in the structure and proportion of its wings, and of a reptile in the smallness of its head and in its beak, armed with at least sixty equal sharp-pointed teeth, differing little in form and size.

Dr. Buckland describes eight distinct species, varying in size from a snipe to a cormorant. Of these, _P. cra.s.sirostris_ (Fig. 105) and _P.

brevirostris_ (Fig. 106), were both discovered in the Lias of Solenhofen. _P. macronyx_ belongs to the Lias of Lyme Regis.

The Pterodactyle was, then, a reptile provided with wings somewhat resembling those of Bats, and formed, as in that Mammal, of a membrane which connected the body with the excessively elongated phalanges of the fourth finger, which served to expand the membrane that answered the purposes of a wing. The Pterodactyle of the Lia.s.sic period was, as we have seen, an animal of small size; the largest species in the older Lias beds did not exceed ten or twelve inches in length, or the size of a raven, while the later forms found fossil in the Greensand and Wealden beds must have measured more than sixteen feet between the tips of the expanded wings. On the other hand, its head was of enormous dimensions compared with the rest of the body. We cannot admit, therefore, that this animal could really fly, and, like a bird, beat the air. The membranous appendage which connected its long finger with its body was rather a parachute than a wing. It served to moderate the velocity of its descent when it dropped on its prey from a height. Essentially a climber, it could only raise itself by climbing up tall trees or rocks, after the manner of lizards, and throw itself thence to the ground, or upon the lower branches, by making use of its natural parachute.

The ordinary position of the Pterodactyle was probably upon its two hind feet, the lower extremities being adapted for standing and moving on the ground, after the manner of birds. Habitually, perhaps, it perched on trees; it could creep, or climb along rocks and cliffs, or suspend itself from trees, with the a.s.sistance of its claws and feet, after the manner of existing Bats. It is even probable, Dr. Buckland thought, that it had the power of swimming and diving, so common to reptiles, and possessed by the Vampyre Bat of the island of Bonin. It is believed that the smaller species lived upon insects, and the larger preyed upon fishes, upon which it could throw itself like the sea-gull.

The most startling feature in the organisation of this animal is the strange combination of two powerful wings attached to the body of a reptile. The imagination of the poets long dwelt on such a combination; the _Dragon_ was a creation of their fancy, and it played a great part in fable and in pagan mythology. The Dragon, or flying reptile, breathing fire and poisoning the air with his fiery breath, had, according to the fable, disputed with man the possession of the earth.

G.o.ds and demiG.o.ds claimed, among their most famous exploits, the glory of having vanquished this powerful and redoubtable monster.

Among the animals of our epoch, only a single reptile is found provided with wings, or digital appendages a.n.a.logous to the membranous wings of the bats, and which can be compared to the Pterodactyle. This is called the _Dragon_, one of the Draconidae, a family of Saurians, which has been described by Daudin, as distinguished by the first six ribs, instead of hooping round the abdomen, extending in nearly a straight line, and sustaining a prolongation of skin which forms a sort of wing a.n.a.logous to that of the Pterodactyle. Independent of the four feet, this wing sustains the animal, like a parachute, as it leaps from branch to branch; but the creature has no power to beat the air with it as birds do when flying. This reptile lives in the forests of the hottest parts of Africa, and in some isles of the Indian Ocean, especially in Sumatra and Java. The only known species is that figured at page 238 (Fig. 107), which comes from the East Indies.