supply of more stimulating diet." All the groups of Jurassic Reptiles which we have hitherto been considering are wholly unrepresented at the present day, and do not even pass upwards into the Tertiary period. It may be mentioned, however, that the Oolitic deposits have also yielded the remains of Reptiles belonging to three of the existing orders of the class-namely, the Lizards (_Lacertilia_), the Turtles (_Chelonia_), and the Crocodiles (_Crocodilia_). The Lizards occur both in the marine strata of the Middle Oolites and also in the fresh-water beds of the Purbeck series; and they are of such a nature that their affinities with the typical Lacertilians of the present day cannot be disputed. The Chelonians, up to this point only known by the doubtful evidence of footprints in the Permian and Triassic sandstones, are here represented by unquestionable remains, indicating the existence of marine Turtles (the _Chelone planiceps_ of the Portland Stone). No remains of Serpents (_Ophidians_) have as yet been detected in the Jurassic; but strata of this age have yielded the remains of numerous _Crocodilians_, which probably inhabited the sea. The most important member of this group is _Teleosaurus_, which attained a length of over thirty feet, and is in some respects allied to the living Gavials of India. [Illustration: Fig. 181.--_Archoeopteryx macrura_, showing tail and tail-feathers, with detached bones. Reduced. From the Lithographic Slate of Solenhofen.] [Illustration: Fig. 182.--Restoration of _Archoeopteryx macrura_. (After Owen.)]