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which the species has passed--this is true in Man as well as in the Frog. We need not tarry long in considering the Reptile family of living forms. In its varieties of serpents, lizards, crocodiles, turtles, etc., we have studied and observed its forms. We see the limbless snakes; the lizards with active limbs; the huge, clumsy, slow crocodiles and alligators--the armor-bearing turtles and tortoises--all belonging to the one great family of Reptiles, and nearly all of them being degenerate descendants of the mighty Reptile forms of the geological Age of Reptiles, in which flourished the mighty forms of the giant reptiles--the monsters of land and water. Amidst the dense vegetation of that pre-historic age, surrounded by the most favorable conditions, these mighty creatures flourished and lived, their fossilized skeleton forms evidencing to us how far their descendants have fallen, owing to less favorable conditions, and the development of other life-forms more in harmony with their changed environment. Next comes the great family of Birds. The Birds ascended from the Reptiles. This is the Eastern Teaching, and this is the teaching of Western Science It was formerly taught in the text-books that the line of ascent was along the family of winged reptiles which existed in the Age of Reptiles, in the early days of the Earth. But the later writers on the subject, in the Western world, have contradicted this. It is now taught that these ancient winged-reptiles were featherless, and more closely resembled the Bat family than birds. (You will remember Chapter XVIII 60 that a Bat is neither a reptile nor a bird--it is a mammal, bringing forth its young alive, and suckling them at its breast. The Bat is more like a mouse, and its wings are simply membrane stretched between its fingers, its feet, and its tail.) The line of ascent from Reptile to Bird was along the forms of the Reptiles that walked on land. There are close anatomical and physiological relations and correspondences between the two families (Reptiles and Birds) which we need not refer to here. And, of course, many modifications have occurred since the "branching-out." The scales of the reptiles, and the feathers of the birds, are known to be but modifications of the original outer skin, as are also the hair, claws, hoofs, nails, etc., of all animals. Even teeth arose in this way, strange as it may now seem--they are all secreted from the skin. What a wonderful field for thought--this gradual evolution from the filmy outer covering of the lowest living forms to the beautiful feathers, beaks, and claws of the bird! The evolving of wings meant much to the ascending forms of life. The Reptiles were compelled to live in a narrow circle of territory, while the Birds were able to travel over the earth in wide flights. And travel always develops the faculties of observation, memory, etc., and cultivates the senses of seeing, hearing, etc. And the creature is compelled to exercise its evolving "thinking" faculties to a greater extent. And so the Birds were compelled by necessity of their travels to develop a greater degree of thinking organism. The result is that among birds we find many instances of intelligent thought, which cannot be dismissed as "mere instinct." Naturalists place the Crow at the head of the family of Birds, in point of intelligence, and those who have watched these creatures and studied the mental processes, will agree that this is a just decision. It has been proven that Crows are capable of counting up to several figures, and in other ways they display a wonderful degree of almost human sagacity. Next above the Bird family comes the highest form of all--the Mammals. But before we begin our consideration of these high forms, let us take a hasty glance at the "connecting-links" between the Birds and the Mammals. The lowest forms of the Mammals resemble Birds in many ways. Some of them are toothless, and many of them have the same primitive intestinal arrangements possessed by the birds, from which arises their name, Monotremes. These Monotremes may be called half-bird and half-mammal. One of the most characteristic of their family is the _Ornithorhynchus_, or Duck-bill, which the early naturalists first thought was a fraud of the taxidermists, or bird-stuffers, and then, when finally convinced, deemed it a "freak-of-nature." But it is not a freak creature, but a "connecting-link" between the two great families of creatures. This animal presents a startling appearance to the observer who witnesses it for the first time. It resembles a beaver, having a soft furry coat, but also has a horny, flat bill like a duck, its feet being webbed, but also furnished with claws projecting over the edge of the web-foot. It lays eggs in an underground nest--two eggs at a time, which are like the eggs of birds, inasmuch as they contain not only the protoplasm from which the embryo is formed, but also the "yolk." on which the embryo feeds until hatched. After the young Duck-bill is hatched, it feeds from teatless glands in the mother's body, the milk being furnished by the mother by a peculiar process. Consider this _miracle_--an animal which lays eggs and then when her young are hatched nourishes them with milk. The milk-glands in the mother are elementary "breasts." The above-mentioned animal is found in Australia, the land of many strange forms and "connecting-links," which have survived there while in other parts of the globe they have vanished gradually from existence, crowded out by the more perfectly evolved forms. Darwin has called these surviving forms "living fossils." In that same land is also found the Echidna or spiny ant-eater, which lays an egg and then hatches it in her pouch, after which she nourishes it on milk, in a manner similar to that of the Duck-bill. This animal, like the Duck-bill, is a Monotreme. Scientists are divided in theories as to whether the Monotremes are actually descended directly from the Reptiles or Birds, or whether there was a common ancestor from which Reptiles and Birds and Mammals branched off. But this is not important, for the relationship between Reptiles, Birds and Mammals is clearly [ Pobierz całość w formacie PDF ] |