animals that have lived at a former period of the world's history, but have at present no representatives, we shall find,—to again quote our previous authority, "Among the Mammalia and birds there are none (orders) 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."[1] Amphibia, however, certainly existed, and were apparently abundant in the Carboniferous age; and, as Mr. Thomson remarks, "the food of adult amphibians usually consists of insects, slugs, and worms."[2] We may surmise that many were arboreal in their habits, and these, before the advent of the true reptiles and birds, must have constituted the principal insect enemies. We must also recollect that the Pterodactyles, or Flying Dragons, during the long reptilian period, "played the rôle of the bats and birds of the present day."[3] The imperfection of the geological record is, however, no argument against evolution, though it seems strange it has not even been made of much more use by some opponents. The struggle for life is an ancient one, but the combatants have not always been the same. In Pliocene times, as Prof. Owen has stated, "Bats, Moles, and Shrews were then, as now, the forms that preyed upon the insect world in this island."[4] The number of mammals which devour insects seem sometimes overlooked, and this fact can be easily realized by looking through the pages of any good treatise on the Mammalia, and tabulating the nature of the food used by the different animals. For the purpose of the present discussion it should be remembered, as remarked by Mr. W.L. Sclater, that the conclusion is more than probable "that before the commencement of the Tertiary epoch the whole world was, so far as is at present known, inhabited by small insignificant mammals distinctly allied to the marsupials."[5]
Perhaps one of the inevitable faiths is that of the man of science who neither disguises the necessity of the halt, nor disbelieves in the certainty of the forward march, and these Carboniferous
