Generally speaking, the carnivorous mammalia respect one another: lion does not war with tiger, nor the leopard contend with the hyena. But the carnivorous reptiles manifest no such respect for the carnivorous mammals. There are fierce contests in their native jungles, on the banks of the Ganges, between the gavial and the tiger; and in the steaming forests of South America, the boa-constrictor casts his terrible coil scarce less readily round the puma than the antelope. A world which, after it had become a home of the higher herbivorous and more powerful carnivorous mammals, continued to retain the gigantic reptiles of its earlier ages, would be a world of horrid, exterminating war, and altogether rather a place of torment than a scene of intermediate character, in which, though it sometimes reëchoes the groans of suffering nature, life is, in the main, enjoyment. And so,—save in a few exceptional cases, that, while they establish the rule as a fact, serve also as a key to unlock that principle of the Divine government on which it appears to rest,—no sooner was the reptile removed from his place in the fore-front of creation, and creatures of a higher order introduced into it the consolidating and fast-ripening planet of which he had been so long the monarch, than his bulk shrank and his strength lessened, and he assumed a humility of form and aspect at once in keeping with his reduced circumstances, and compatible with the general welfare. But though the _reason_ of the reduction appears obvious, I know not that it can be referred to any other _cause_ than simply the will of the All-Wise Creator.