with which we are acquainted as existing on the earth at the present day, and it is only possible here to briefly note some of the more important of these ancient forms.  Amongst the group of the Lizards (Lacertilia), represented by Protorosaurus in the older Permian strata, three types more or less certainly referable to this order may be mentioned.  One of these is a small reptile which was found many years ago in sandstones near Elgin, in Scotland, and which excited special interest at the time in consequence of the fact that the strata in question were believed to belong to the Old Red Sandstone formation.  It is, however, now certain that the Elgin sandstones which contain Telerpeton Elginense, as this reptile is termed, are really to be regarded as of Triassic age.  By Professor Huxley, Telerpeton is regarded as a Lizard, which cannot be considered as “in any sense a less perfectly-organised creature than the Gecko, whose swift and noiseless run over walls and ceilings surprises the traveller in climates warmer than our own.”  The “Elgin Sandstones” have also yielded another Lizard, which was originally described by Professor Huxley under the name of Hyperodapedon, the remains of the same genus having been subsequently discovered in Triassic strata in India and South Africa.  The Lizards of this group must therefore have at one time enjoyed a very wide distribution over the globe; and the living Sphenodon of New Zealand is believed by Professor Huxley to be the nearest living ally of this family.  The Hyperodapedon of the Elgin Sandstones was about six feet in length, with limbs adapted for terrestrial progression, but with the bodies of the vertebrae slightly biconcave, and having two rows of palatal teeth, which become worn down to the bone in old age.  Lastly, the curious Rhynchosaurus of the Trias is also referred, by the eminent comparative anatomist above mentioned, to the order of the Lizards.  In this singular reptile (fig. 151) the skull is somewhat bird-like, and the jaws appear to have been destitute of teeth, and to have been encased in a horny sheath like the beak of a Turtle or a Bird.  It is possible, however, that the palate was furnished with teeth.

[Illustration:  Fig. 151.—­Skull of Rhynchosaurus articeps.  Trias.  (After Owen.)]

The group of the Crocodiles and Alligators (Crocadilia), distinguished by the fact that the teeth are implanted in distinct sockets and the skin more or less extensively provided with bony plates, is represented in the Triassic rocks by the Stagonolepis of the Elgin Sandstones.  The so-called “Thecodont” reptiles (such as Belodon, Thecodontosaurus, and Paloeosaurus, fig. 152, c, d, e) are also nearly related to the Crocodiles, though it is doubtful if they should be absolutely referred to this group.  In these reptiles, the teeth are implanted in distinct sockets in the jaws, their crowns being more or less compressed and