_The Permian flora and fauna._ The Permian flora presents some difficulties. The flora of the Zechstein consists largely of ferns and conifers, but that of the Rothliegende of Germany has been compared with that of the Carboniferous, and if a true Permian flora of the northern hemisphere has many forms of Carboniferous affinities, the presence of the Glossopteris flora in Permo-Carboniferous rocks of more southerly regions seems to imply its origin there and _slow_ migration northwards. It must be noted, however, that the Rothliegende has been divided by some geologists into an upper and lower division, of which the lower is actually referred to the Carboniferous system. All that can be now said is, that our knowledge of the floras of Permo-Carboniferous and Permian times is still incomplete, and that the difficulties will no doubt be cleared up as the result of further work. The invertebrate fauna of the north-west European Permian deposits is chiefly noticeable on account of the paucity of species, though individuals are often abundant. The shells are also sometimes stunted and occasionally distorted. These characters bear out the supposition that the aqueous deposits were laid down in inland seas of Caspian character and not in the open ocean. Polyzoa, brachiopods, and lamellibranchs predominate, but other groups are found. The vertebrates consist of forms of fish, amphibia and reptiles, and the Permian rocks are the earliest strata in which the remains of true Reptilia are known to occur with certainty. The Reptiles belong to the orders Anomodontia (Theromora) and Rhynchocephalia, of which the former is exclusively Permian and Triassic, while the latter is abundant in the strata of those periods, but is represented at the present day by the genus _Sphenodon_ of New Zealand. The Amphibia belong to the order Labyrinthodontia which ranges from Carboniferous to Lower Jurassic, but the members of the order are most abundant in Permian and Triassic strata, and these periods may be spoken of as the Periods of Labyrinthodonts.