« السابقةمتابعة »
ber of individuals. Life is a gift which the Creator dispenses with an equal hand to those on whom it is conferred. The amount of happiness which it brings seems to be in the inverse ratio of the time of its enjoyment; and the being that riots for a day in the light and heat of the sunbeam, would perhaps not exchange its ephemeral elysium for the protracted and often miserable centuries of an antediluvian existence. Nor does the manner in which that life is brought to a close at all affect the determinate quantity of its felicity. The religious feelings, and human sympathies, and secular interests which preside at the deathbed of man, impel us to watch with double care over sickness, and decrepitude, and age, and to protract to the last moment even the agonies by which we are appalled. In the world of instinct, however, where the affections have but a limited range, a quick and a violent death becomes the truest charity. The tiger is at once the doctor, the lawyer, the sexton, and duary legatee of the peaceful occupants of his native jungle.
But this law of destructive happiness is not confined, as Dr Buckland should have mentioned, to the irrational world. Though his species cannot boast of any lethal mechanism which combines, like the teeth of the Megalosaurus, the slaying power of the • sabre, the knife, and the saw, and cannot therefore charge their carnivorous deeds either upon their claws or their teeth, yet the history of man is written in the blood of his fellows, and feats of cruelty and violence emblazon the chronicle even of his amusements. In the battles of ambition, where bloodthirsty myrmidons pant for the destruction of their kind—in the enactment and toleration of sanguinary laws—in acts of ignorant and profligate legislation by which millions are starved and expatriated and in those nameless deeds of injustice and persecution by which power does slow execution upon its victims, we may match the most sanguinary acts of the most sanguinary age of carnivorous ascendency.
Dr Buckland is now brought, in virtue of his arrangement, to consider the proofs of design exhibited in the specific structures of fossil animals. He begins with the fossil mammalia, or those animals that give suck to their young; but as the greater number of the earliest fossil animals of this class differ in few essential points from their living representatives, be selects the two extinct genera of the Dinotherium and the Megatherium--the first, the largest of the terrestrial mammalia, and the second, the one that deviates most from the ordinary forms of animal life.
The remains of the Dinotherium occur most abundantly in Hesse-Darmstadt. Both Cuvier and Kaup calculate the size of the largest species, the Giganticum, to have been eighteen feet in length. Its shoulder-hlade, resembling that of a mole, indicates an adaptation of the fore-leg to the purposes of digging. It differs from all other quadrupeds in carrying at the extremity of its lower jaw, which is twelve feet long, two enormous tusks, which Dr Buckland considers as instruments for raking and grubbing up the roots of large aquatic vegetables, combining the powers of the pickaxe with those of the horse-harrow. He conceives also that these tusks might be used to hook the head of the animal to the bank of a lake or river, where it might repose itself while floating on the water. Hence he regards it as a herbivorous aquatic quadruped, adapted to the lacustrine condition of the earth during the tertiary periods.
The Megatherium, which has been fully described by Cuvier, is a most extraordinary animal, nearly allied to the sloth, with the same apparent monstrosity, and many singular peculiarities of structure. An engraving, of which Dr Buckland has given a very beautiful
to convey an idea of it; and as we cannot abridge our author's long and interesting account of ils peculiar structure we must content ourselves with referring to the work itself.*
The gigantic character of these indwellers of the lakes have induced Dr Buckland to give them the precedence of the very old family of the Saurians; so that we must now go back to the early age of the secondary strata to contemplate the earth when inhabited by crocodiles and lizards of various forms, * and often of gigantic size; fitted to endure the turbulence and con'tinual convulsions of the unquiet surface of our infant world.' These strange animals were not only the principal occupants and the dreaded tyrants of the dry land, but they exercised a dominion also over the waters of the sea.
The name of Ichthyosaurus, or fish-lizard, has been given to
* Dr Buckland mentions, in a supplementary note, the discovery of a large fossil animal in the valley of the Markanda, in the Sivalic or sub-Himalayan range of bills between the Jumna and the Ganges. It exceeds in size the largest rhinoceros, and forms an important link between the Ruminantia and the Pachydermata. The head was found nearly entire; and more recently, Captain Cautley has discovered a portion of the skeleton in another part of the bills. These last portions, however, seem to have been lost. Dr Falconer's and Captain Cautley's account of the Sivatherium, will be found in the London and Edinburgh Phil. Journal, for September and October, 1836, p. 193, 277.
some of the most remarkable of these reptiles, which possess • combinations of forin and mechanical contrivances which are . now dispersed through various classes and orders of existing
animals, but are no longer united in the same genus.' In its general outline the Ichthyosaurus resembles the modern porpoise or grampus. It combines the snout of a porpoise, the teeth of a crocodile, the head of a lizard, the sternum ofan ornithorynchus, with the paddles of a whale. It has a long and powerful tail, and the total length of some of the largest must have exceeded thirty seet.
The most extraordinary feature of this singular animal is the enormous magnitude of its eye; which is such, that in a skull of the Ichthyosaurus platyodon, in the collection of Mr Johnson at Bristol, the larger diameter of the orbital cavity is fourteen inches! The following are Dr Buckland's observations on this singular optical instrument:-
* From the quantity of light armitted in consequence of its prodigious size, it must have possessed very great powers of vision; we have also evidence that it had both microscopic and telescopic properties. We find on the front of the orbital cavity, in which this eye was lodged, a circular series of petrified thin bony plates, ranged around a central aperture, where once was placed the pupil; the form and thickness of each of these plates very much resembles that of the scales of an artichoke. In living animals these bony plates are fixed in the exterior or sclerotic coat of the eye, and vary ils scope of action, by altering the convexity of the cornea; by their retraction they press forward the front of the eye, and convert it into a microscope ; in resuming their position, when the eye is at rest, they convert it into a telescope.'
We have quoted this passage in order to enliven the monotony of our praise by a single note of censure; and in the hope also that Dr Buckland will remodel it in another edition. Even if the physiology of the passage were correct, we should object strongly to the statement that the eye of any animal which has the power of adjustment to different distances-and what animal has not this power?-possesses microscopic and telescopic prop ties. The general reader cannot fail to regard these properties as peculiarly belonging to the huge eye of the Ichthyosaurus, which Dr Buckland does not mean to insinuate. With regard to the use of the bony circle it is a most gratuitous hypothesis to make it the mechanism of adjustment to different distances. Even in the human eye, upon which we can make endless experiments, we know nothing of the mechanism of adjustment; and if Kepler, and Newton, and the most distinguished of their successors, aided with all the skill of the optician and the anatomist, wings, terminated by long hooks like the curved claw on the bat's tumb; and their bodies and tail approximate to those of common mammalia. Dr Buckland conjectures that the Pterodactyle had also the power of swimming, like the vampyre bat of the island of Bonin.
Next to the flying Saurians our author places the gigantic terrestrial Saurians—the megalosaurus and the iguanodon. The genus megalosaurus was established by Dr Buckland in 1824, from specimens found in the Oolitic slate of Stonesfield, near Oxford. Cuvier conceives it to have been an enormous reptile, measuring from forty to fifty feet in length, and partaking of the structure of the crocodile and monitor. The form of its teeth shows it to have been in a high degree carnivorous, and it is supposed to have fed on smaller reptiles,—such as crocodiles and iortoises, whose remains are found in abundance in the same strata. The most important part of this land lizard yet found, is a fragment of the lower jaw, containing many teeth, whose mechanism combines the properties of the knife, the sabre, and the saw.
The genus Iguanodon, or the gigantic terrestrial Saurian, we owe to the indefatigable labours of Mr Mantell, who discovered its insulated bones in the Wealden freshwater formation of the South of England. So lately as 1834, a very large part of the skeleton ofthis aninal has been found in more recent strata in the quarries of Kentish Rag near Maidstone. This skeleton is now in Mr Mantell's museum, and confirms nearly all his deductions from the insulated bones he had previously found. From the analogy between this herbivorous animal, and the modern iguana, he has computed the dimensions of the iguanodon ; and found its total lengih to be seventy feet, its tail fifty-two and a half feet long, and its body fourteen and a hall feet round.
Passing over the amphibious saurians allied to crocodiles, which do not differ greatly from existing genera, we come to the fossil tortoises or testudinata, which have acquired special honour among fossil animals, by having left the traces of their footsteps distinctly imprinted on the solid rock. This curious discovery was made hy Dr Henry Duncan of Ruthwell, who observed them on sandstone in the quarry of Corncockle muir in Dumfries-shire; and similar impressions have been recently observed in several quarries of grey sandstone at the village of Hessberg, near Hildburghausen, in Saxony. The specimens discovered by Dr Duncan have been carefully preserved by him, and placed in the summer-house of bis garden, where we have had the good fortune of seeing them. The beauty and distinctness of the footsteps are poorly represented in the best engravings, or even in the plaster casts we have seen; and it is impossible to look at them without the instantaneous conviction that an aniinal has walked over the sandstone when in a soft condition. Dr Buckland has come to the conclusion that the footsteps were those of land tortoises; in consequence of comparing the impressions made by an Emys and Testudo Græca while walking over soft sand and clay, and upon unbaked pie-crust. Sir William Jardine has observed similar impressions in quarries near Corncockle muir; and they have also been discovered in the red sandstone quarries of Craigs, near Dumfries. But the most remarkable of all the footsteps that have yet been discovered are those recently described and figured by Professor Hitchcock, in the American Journal of Science. They occur in the new red sandstone of the valley of the Connecticut, and belong to two gigantic birds which are now extinct. One series of these impressions belong to a bird twice the size of an ostrich, whose foot measured fifteen inches in length, exclusive of the largest claw, which was two inches long. Six of these footsteps appeared in regular succession, at distances varying from four to six feet. - Another series of these gigantie footsteps exhibits the marks of three toes of a more slender character. The foot has been from fifteen to sixteen inches long, exclusive of a curious appendage extending eight or nine inches behind the heel, and apparently intended, according to Dr Buckland, like a snow shoe, to sustain the weight of a heavy animal walking upon a soft bottom. The impres- sions of this appendage resemble those of wiry feathers, or coarse
bristles, which seem to havesunk into the mud and sand nearly an • inch deep; the toes had sunk much deeper, and round their impressions the mud was raised into a ridge several inches high, like ihat around the track of an elephant in clay. The length of the step of this bird appears to have been sometimes six feet.' Dr Buckland has illustrated his description of these most singular phenomena with no fewer than six large plates.
The next subject which engages our author's attention is the most important one of Fossil fishes. Hitherto our knowledge of existing fishes has been very imperfect. Cuvier had undertaken their classification some time before his death, and had observed no fewer than eight thousand different species; but seeing the impossibility of overtaking such a task, he consigned all his materials into the hands of Professor Agassiz of Neuchatel, who has distinguished himself above all other naturalists in this department of Natural History. He has given a new classification of existing species, founded on the character of their scales. In his first order of the Placoideans, the scales consist of broad plates of enamel, passing, as in the shark, into points. The second order of the Ganoideans is distinguished by angular scales, with a bright sur