[315] Some may be astonished at our applying the word _kingdom_ to the vertebrata. We do so because, in truth, the distance which separates them from other animals seems to us almost as great, and even more decided, than that which separates the invertebrata from plants. [316] The diagram which Darwin has placed in his book _On the Origin of Species_, is only a fraction and piece of detail of the general figure which we are endeavouring to place before the mind of the reader. [317] _L’Insecte_, p. 128, 1858. [318] Predominance of the immediate azotic principles, respiration comparable to that of animals, voluntary movements, indivisibility of organism, etc. [319] [See above, pp. 46, 47.--EDITOR.] [320] See _On the Origin of Species_, chap. iii. [321] Lions hindered the army of Xerxes in Macedonia. They abounded in the province of Africa in the time of the Roman Emperors. At the present time, however, Gérard was obliged to watch for three hundred nights in order to kill only thirty or forty. [322] The crocodile, which used to swarm on the Delta, is now only found in Upper Egypt. [323] The hippopotamus, since the Roman occupation, has successively retired from the mouth of the Nile to the fourth cataract. Some years ago, there existed one, and one only, at the Island of Argo, on this side of New Dongolah. Some hunters killed it, and since then, they have only been found at the Berber level. [324] [_Hamites_, a genus of extinct Cephalopods, found in the greensand formation in England.--EDITOR.] [325] _Comptes Rendus_, vol. iv, p. 58. Perhaps the only logical deduction which we can really draw from the greater size of these animals, is the greater extent of the continents which they inhabited. The belief in the gigantic dimensions of the fossil _fauna_ and _flora_, is also a remains of the marvels which the first inquirers into science involuntarily reported. In examining matters nearer and more impartially, we see that certain zoological groups have been, in fact, formerly represented by larger species than at the present day; but until we arrive at some new discovery, we have the right to think that the other groups of animals, on the contrary, have a class of larger representatives _than in former times_; like the quadrumana, the cetacea, insects, cephalopods, acephalous mollusks, etc. But this pretended decay is especially false as regards plants; if we find in the ground some large ferns, or enormous grasses, we must subtract a good deal from those so-called _antediluvian_ forests, which many have not hesitated to bring forward in support of their ideas. All the fossil plants that we know are, without exception, extremely wretched in comparison with the gigantic conifers and dicotyledons in the forests of the old and new world.