The great value of the hatteria now, is the light which it throws on obscure points in the structure of its fossil relatives. Helpless and inert, it seems to belong rather to past ages and to the dead, than to to-day and the living. FOOTNOTES: [50] Nature Reader, No. 1, Lessons 1-6. [51] Nature Reader, No. 3, Lesson 45. LESSON XXIII. THE ANCIENT BUILDER. “Again the mossy earth looks forth, again the streams run clear; The fox his hillside cell forsakes, the musk rat leaves his nook, The blue-bird in the meadow brakes is singing with the brook; ‘Bear up, O mother nature,’ cry bird, breeze, and streamlet free, ‘Our winter voices prophesy of summer days to thee.’” --WHITTIER. [Illustration: THE WONDERFUL BUILDER.] One of the most celebrated animals in the world is the beaver. This creature belongs to the mammalian order, Rodentia, or the “gnawers.” The mammals of this order are distinguished by their strong, chisel-shaped front teeth. They have a greater number of species, and a wider distribution over the earth than any other terrestrial mammals. To this order belong squirrels, rabbits, rats, mice, and many other species, and the order, as a whole, will be briefly described in a later chapter. At present we must fix our attention upon the beaver, which Buffon said constituted such a link between quadrupeds and fishes, as is the bat between quadrupeds and birds. In fact neither bat nor beaver is a link between different orders, but the beaver is nearly as aquatic in its habits as a fish, and its tail is about as well covered with scales as is the body of a fish. The beaver is an animal of great geologic age: its fossil remains have been found freely distributed over northern Europe, Asia, and America. At present it has entirely disappeared from many countries where formerly it abounded. In some places in Europe it has abandoned many of its most peculiar and interesting habits of life, and sunk slowly to nearly the condition of its distant relative, the water-rat. In truth, the beaver, like the king-crab, is a creature evidently doomed to extinction. The cause of the rapid disappearance of the beaver is the value of its fur, which has caused it to be hunted with a reckless disregard of the danger of destroying the entire family. The story of the fate of the goose which laid golden eggs is not wholly a fable, but holds true of many valuable and beautiful plants and animals, which human greed has ruthlessly destroyed. The beaver no doubt had a very happy time building its huts and dams, feeding on roots and bark, and swimming merrily in the rivers, before men were known upon the earth.