The Past Condition of Organic Nature by Thomas Henry Huxley
page 19 of 21 (90%)
page 19 of 21 (90%)
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animals is a sort of way of comparing the past creation as a whole with
the present as a whole. Among the mammalia and birds there are none extinct; but when we come to the reptiles there is a most wonderful thing: out of the eight orders, or thereabouts, which you can make among reptiles, one-half are extinct. These diagrams of the plesiosaurus, the ichthyosaurus, the pterodactyle, give you a notion of some of these extinct reptiles. And here is a cast of the pterodactyle and bones of the ichthyosaurus and the plesiosaurus, just as fresh as if it had been recently dug up in a churchyard. Thus, in the reptile class, there are no less than half of the orders which are absolutely extinct. If we turn to the 'Amphibia', there was one extinct order, the Labyrinthodonts, typified by the large salamander-like beast shown in this diagram. No order of fishes is known to be extinct. Every fish that we find in the strata--to which I have been referring--can be identified and placed in one of the orders which exist at the present day. There is not known to be a single ordinal form of insect extinct. There are only two orders extinct among the 'Crustacea'. There is not known to be an extinct order of these creatures, the parasitic and other worms; but there are two, not to say three, absolutely extinct orders of this class, the 'Echinodermata'; out of all the orders of the 'Coelenterata' and 'Protozoa' only one, the Rugose Corals. So that, you see, out of somewhere about 120 orders of animals, taking them altogether, you will not, at the outside estimate, find above ten or a dozen extinct. Summing up all the orders of animals which have left remains behind them, you will not find above ten or a dozen which cannot be arranged with those of the present day; that is to say, that the difference does not amount to much more than ten per cent.: and the |
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