10 ILLUSTRATED NATURAL HISTORY. 



'The fion.l, 

 O'er I"".', o'er steep, through straight, rough, dense, or rare, 

 With head, hands, wings, or feet, pursues his way, 

 And swims, or wades, or creeps, or flies. 1 



"With links of such creatures flying in the air, and shoals of no less monstrous ichthyosauri 

 and plesiosauri swarming in the ocean, and tortoises crawling on the shores of the primeval lakes 

 and rivers, — air, sea, and land must have been strangely tenanted in these early periods of our 

 infant world." 



In Bpeaking of this age of reptiles, the period of the iguanodon, Dr. Mantell says : "The country 

 it inhabited must have been diversified by hill and dale, by streams and torrents, the tributaries ol 

 its mighty rivers. Arborescenl ferns, palms, and 3 uccas constituted its groves and forests ; delicate 

 ferns and grasses, the vegetable clothing of its soil; and in its marshes, equiseta, and plants of a 

 like nature, prevailed. It was peopled by enormous reptiles, among which the colossal iguanodon 

 and the megalosaurus were the chief. Crocodiles and turtles, flying reptiles and birds, frequented 

 its fens and rivers, and deposited their eggs on the hanks and shoals; and its waters teemed with 

 lizards, fishes, and mollusca. But there is no evidence that man ever set his foot upon that 

 wondrous soil, or that any of the animals which arc his contemporaries found there a habitation; 

 on the contrary, not only is evidence of their existence altogether wanting, but, from numberless 

 observations made in everj part of the globe, there are conclusive reasons to infer that man and 

 the existing races of animals were not created till myriads of years after the destruction of the 

 iguanodon country, — a country which language can hut feebly portray, but which the magic 

 pencil of a Martin, by the aid of geological research, has rescued from the oblivion of the past, 

 and placed before us in all the hues of nature, with its appalling dragon-forms, its forests of palms 

 and tree-ferns, and the luxuriant vegetation of a tropical clime." 



These are some of the extinct animal wonders which geology presents to our view. There were, 

 however, almost countless species of others, inferior in size, hut often no less curious in their 

 structure and endowments. These include whole races of quadrupeds, birds, fishes, reptiles, insects, 

 and still lower organizations. There is hardly a single existing animal which has not its semblance 

 in this field of fossil wonders. It would seem that for millions of ages the earth has been the 

 theater of a succession of creations of animal forms; and so multitudinous are these, that the crust 

 of the globe is, in greal fait, composed of their relics. A celebrated author says that "there is 

 hardly an atom of its rocks and soil which has not passed through the complex and wonderful 

 laboratory of life." All the orders of animals, from the highest to the lowest, have contributed to 

 swell the amount of the solid materials of the earth. It is supposed that limestone constitutes one- 

 nth part of the crust of the globe; and this, with the immense beds of chalk, flint, marl, gyp- 

 sum, sandstone, lias, and jasper, are all of animal origin. They arc, in fact, the bones and shells of 

 the innumerable races which have lived on the earth in ages past, and which, for the most part, 

 have become extinct. 



The subject of organic remains constitutes of itself a separate science, to which is given the 

 name t,{ Paleontology. The classification of extinct animals has been pursued with great zeal, and 

 nearly 25,000 species have been identified. This is a field of wonders, calculated to enlarge our 

 view of the boundaries of creation ; but we must now take leave of it, and give attention to those 

 animal races winch constitute the living inhabitants of our globe. 



PRELIMINARY REMARKS ON THE CLASSIFICATION OF ANIMALS. 



When we consider the immense number of animals existing on the face of the earth, wc are soon 

 convinced that an attempt to obtain a knowledge of each of them individually, and without any 

 acquaintance with their mutual relationships, would be a hopeless task. We are, in fact, compelled 

 to call in the aid of some system of classification, which, by bringing together those animals which 

 most resemble each other, and characterizing them by some common point of structure, may enable 

 us to form a general idea of the whole, ami thus to remember more readily the -peculiarities of 

 each. Some Buch classification, rough and imperfect as it may be, i>. indeed, formed by every obser- 

 vant mind; and its terms find a place in ordinary language. Beasts, birds, and fishes, reptiles, 



