Reptilia

“ The class Reptilia includes the lizards, snakes, tortoises, turtles, crocodiles, and alligators. Although popularly associated in the common mind with the batrachians, the reptiles are really more nearly related to the birds than to the salamanders and frogs. In general shape they more nearly resemble the batrachians, but in the structural condition of the internal body organs they are more like the birds. They are cold-blooded, and breathe exclusively by means of lungs, the forms which live in water coming to the surface to breathe. ”

“ When we contrast the grand development and notable modifications of the extinct species of Reptilia with the poor scanty evidences of the class still lingering on in life, we seem to be witnessing a course of degeneration, of retrogradation, rather than of organic progression in the course of time. ”

“ During the Mesozoic age, comparable to the medieval times in human history, reptiles were the dominant forms; they occupied the places in the economy of nature to-day taken by the birds and beasts, both animal and plant feeding, as well as by the whales and other denizens of the air, earth and sea; but among the great reptilian assemblage none were more varied in size, aspect and habits than the dinosaurs or terrible lizards, at that time the peers of the animal realm. ”

“ Probably the snakes are the latest group of equivalent rank to be evolved among the Reptilia, and of the snakes the poisonous vipers are probably among the latest. Most snakes are purely terrestrial in habit; a few are burrowing, and still others are aquatic. And chiefly because of such upland habits they are very scantily represented among fossils, not more than fifty or sixty species altogether ”

“ THE REPTILIA, Or Reptiles, have neither hair, wool, nor feathers, and their bodies are either naked, or covered with scales. Some lay eggs, and some bring forth their young alive. Some have gills, and others lungs, but the latter have only a portion of the blood passing through them; and thus the blood of reptiles is cold, as it is respiration which gives the blood heat. The senses of reptiles are dull, and their movements are either slow or laborious. The following are the four orders into which this class is divided ”

“ In the Jurassic period there were no less than six orders of reptiles which independently abandoned terrestrial life and acquired more or less perfect adaptation to sea life. Nature, limited in her resources for adaptation, fashioned so many of these animals in like form that we have learned only recently to distinguish similarities of analogous habit from the similitudes of real kinship. From whatever order of Mammalia or Reptilia an animal may be derived, prolonged aquatic adaptation will model its outer, and finally its inner, structure according to certain advantageous designs. ”

“ Such relative variety of structure is seen in all imaginings that spring up independently in different regions of the globe, and are yet due to a common belief or cause. Why has he assimilated so much of the reptilian physiognomy and framework? Well, seeing that he had to approximate his shape to some type of beast familiar to mankind, what better general model could have been found? The reptile’s glassy eye; its earthward-creeping and cleft-loving habits; its blood that recalls that chill temperature of stones and water ”

“ It is doubtful whether many of the ‘general public’ imagined these three names to represent the same snake, or whether—except possibly from the last generic one—they could form any idea of the reptile therefrom. Of the many papers that fell under one’s notice, Land and Water alone on this occasion spelt the words correctly. As yet there is no journal devoted to the Reptilia, and the study is evidently not attractive. Nor do we expect all naturalists to be ophiologists ”

“ I conceive that such linear forms, constituting a series of natural gradations between the reptile and the bird, and enabling us to understand the manner in which the reptilian has been metamorphosed into the bird type, are really to be found among a group of ancient and extinct terrestrial reptiles known as the Ornithoscelida. The remains of these animals occur throughout the series of Mesozoic formations, from the Trias to the Chalk, and there are indications of their existence even in the later Palæozoic strata. ”

“ If it had not been for conditions that forced certain reptiles to develop warm-bloodedness, we would have no birds or mammals to-day, for as you doubtless know, birds and mammals both were evolved from reptiles.”
“I swan!” was all the old prospector could say.
“Yes, the first mammals developed from a reptile known as the cynodont. Many of these reptiles had long legs and could travel with the body well off the ground. Birds originated from the same reptilian stock as did the dinosaurs. ”

“ So far as yet known, the reign of reptiles was world-wide in its time; and the imagination is taxed to conceive of a state of things in which the seas swarmed with great reptiles on every coast, when the land was trodden by colossal reptilian bipeds and quadrupeds, in comparison with some of which our elephants are pygmies, and when the air was filled with the grotesque and formidable Pterodactyls. ”

“ But, large as this building is, it would be an easy matter to fill all its available space with the reptiles of North America alone, choosing only the handsome and showy forms. As we contemplate the great number of species in our own reptilian fauna, the thought occurs, what can we do with the reptiles of the Old World? Manifestly, the only proper course is to choose from the reptiles of the world the forms which will make for our visitors and students the most instructive and attractive series of important types. ”

“ As we know comparatively little of the terrestrial reptiles of the triassic or preceding period of the mesozoic age, and very little of its bird-like forms beyond that afforded by the footprints in the Connecticut valley, it is expected by naturalists friendly to the doctrine of evolution that future researches will reveal birds more reptilian than the archæopteryx, and bird-like reptiles, which will go far toward filling the gap which now exists between reptiles and birds. ”

“ Again, our reptiles of the coal do not constitute a continuous series, and belong to a great number of distinct genera and families, nor is it possible that they can all, except at widely different times, have originated from the same source. It either happened, for some unknown reason, that many kinds of fishes put on the reptilian guise in the same period, or else the vast lapse of ages required for the production of a reptile from a fish must be indefinitely increased for the production of many dissimilar reptiles from each other ”

“ Subsequent investigations have brought to light a variety of facts of the same order, the most curious and striking of which are those which prove the existence, in the Mesozoic epoch, of a series of forms intermediate between birds and reptiles—two classes of vertebrate animals which at present appear to be more widely separated than any others. Yet the interval between them is completely filled, in the mesozoic fauna, by birds which have reptilian characters on the one side, and reptiles which have ornithic characters on the other. ”

“ But they certainly also came from the Condylarthra.
There is a remarkable likeness between the history of the development of the reptiles and that of the higher mammals, in one respect, and that is, that they have apparently all been derived from a single order, which occupied the earth at one (an early geological) period. As reptiles are inferior to mammals in the scale, so they are of earlier origin. The primitive reptilian order first appeared in force on the earth during the Permian epoch—that populous time which immediately followed the age of the true coal. ”

“ The idea of birds coming from reptiles is suggested by the following facts: 1st, existing birds have much in common with existing reptiles; 2d, birds and reptiles, at an early period of their existence, cannot be distinguished from one another, as in the case of the embryo chicken and turtle; 3d, the most ancient bird (Archeopteryx) is very reptilian, while certain extinct reptiles (Dinosauria) are very bird-like. These statements are facts accepted by naturalists, whether they are evolutionists or not; they seem to us to harmonize in warranting the conclusion that birds are modified reptiles. ”

“ For instance, the reptilian characters which we recognise in the sauroid fishes, are developed at a later period in animals no longer belonging to the class of fishes, but constituting by themselves new types, provided with additional peculiarities which separate them fully from the fishes in general, as well as from those fishes in which we recognise some relation to reptiles during a period when no reptile existed. ”

“ The reptile now evolved from the amphibian, and a vast reptile population spread over the earth. From one of these early reptiles the birds were evolved. Geology furnishes the missing link between the bird and the reptile in the Archæopteryx, a bird with teeth, claws on its wings, and a reptilian tail. From another primitive reptile the important group of the mammals was evolved. ”

“ The distal ends of these bones correspond in size and relative position in the two groups, but here, in the present specimen, the reptilian features cease, and those of typical Birds replace them. In all the reptiles known hitherto, and especially in Dinosaurs, the second, third, and fourth metatarsals are prominent in front, at their proximal ends, and the third is usually the largest and strongest. In birds, the place of the third is taken above by the second and fourth, the third being crowded backward, and very much diminished in size. ”

“ Remains of Reptiles are very abundant in Triassic deposits, and belong to very varied types. The most marked feature, in fact, connected with the Vertebrate fauna of the Trias, and of the Secondary rocks in general, is the great abundance of Reptilian life. Hence the Secondary period is often spoken of as the "Age of Reptiles." Many of the Triassic reptiles depart widely in their structure from any with which we are acquainted as existing on the earth at the present day, and it is only possible here to briefly note some of the more important of these ancient forms. ”

“ It is an example of an extremely specialised reptile, the loss of the limbs being the most obvious way in which it is specialised from more generalised reptilian types. Specialisation in fact is often synonymous with degradation, and, this being the case, implies a restricted life. ”

“ He thought the present fossil presented some Chelonian characters, but that in many Lizards we may find indications of a dentition similar to that of the fossil. He considered that there could be no doubt as to the connexion between Reptiles and Mammals, and that Prof. Huxley was wrong in his views as to the relationship between Birds and Reptiles. Every mammalian type has a reptilian brain in its earliest stages. ”

“ The differences between a reptile and a bird, on the other hand, are very striking. It might therefore be regarded as a matter for surprise that zoologists now make the greater distinction between the Amphibia and the reptiles, grouping the former in one great class with the fishes, the latter in a second great section with the birds. But in fact there are many fundamental points of agreement between reptiles and birds, and it is impossible to doubt that the latter have sprung from a reptilian stock. Indeed, a most interesting connecting link is known, in the fossil Archiopteryx shown in Fig. ”

“ And thus, while we do not know from these later rocks, and probably never shall from rocks later than the Lower Carboniferous, all of the characters common to the two classes in any one animal, from the comparison of all it is not difficult to decide what were the primitive characters of the reptilian skeleton in almost every detail. ”

“ They dominated until reptiles appeared, when they mostly gave place to—or, as the derivationists will insist, were resolved by divergent variation and natural selection into—common fishes, destitute of reptilian characters, and saurian reptiles, the intermediate grades, which, according to a familiar piscine saying, are "neither fish, flesh, nor good red-herring," being eliminated and extinguished by natural consequence of the struggle for existence which Darwin so aptly portrays. ”

“ We may, for convenience, call these animals reptiles, but they are regarded as belonging to that lower grade of reptilian animals, the Amphibians or Batrachians, which includes the modern frogs and newts and water-lizards.56 Still it would be doing great injustice to the carboniferous reptiles not to say, 153that while related to this low type, they presented a much greater range of organisation than it shows at present, evincing a capability to fill most of the places now occupied by the true reptiles. ”

“ It must be remembered, however, that we know nothing whatever of the hands or feet of the earliest amphibians, and it is purely an assumption that the reptilian hands and feet were evolved from forms like the later ones of Permocarboniferous times. In all probability the embolomerous ancestors of the reptiles had the phalangeal formulae of both front and hind feet like those of the known earliest reptiles. We can hardly conceive of an increase either of the number of digits or number of phalanges in the earliest reptiles. ”