Note 146 — Chapter XV · COMPARISONS AND CONCLUSIONS.

I am quite aware that it may be objected to all this that it is based on merely negative evidence; but this is not strictly the case. There are positive indications of these truths. For example, in the Mesozoic epoch the lacertian reptiles presented huge elephantine carnivorous and herbivorous species—the Megalosaurus, Iguanodon, etc.; flying species, with hollow bones and ample wings—the Pterodactyles; and aquatic whale-like species—Pliosaurus, Ichthyosaurus, etc. These creatures actually filled the offices now occupied by the mammals; and, though lacertian in their affinities, they must have had circulatory, respiratory, and nervous systems far in advance of any modern reptiles even of the order of Loricates.