Very scanty are the early human records of those strange reptiles known as the plesiosaurs. Were one to search through the many works published during the latter half of the seventeenth century and all of the eighteenth, devoted to “lapides petrifacti,” “figured stones,” “reliquia diluvii,” or by whatever other fanciful names fossils were known, here and there he would probably find descriptions and figures of bones of these reptiles. It would hardly seem that plesiosaurian bones could have been overlooked by the curious, so abundant are they in many places. But there is no such history of the early discovery of the plesiosaurs as there is of the ichthyosaurs and mosasaurs. Their birth into human history was very formal and proper, under the ministrations of a learned doctor of science, the renowned Conybeare, of whom we shall speak again. It was he, who with De la Bêche, late Director of the British Geological Survey, described for the first time, in 1823, one of these reptiles, to which he gave the name _Plesiosaurus_, meaning “like a lizard.” He distinguished the plesiosaurs from ichthyosaurs, with which it is possible that they had previously been confounded, and gave a good description of considerable material. Cuvier, a little later, gave a more complete description of the same remains which had served Conybeare and De la Bêche for their original description, and for the first time made it evident that fossil plesiosaurs were widely and abundantly distributed over the earth. The closing sentence of Cuvier’s chapter devoted to the discussion of these creatures in his _Ossemens Fossiles_ was really prophetic, not only of the many discoveries of the plesiosaurs yet to be made, but of all other extinct animals as well: “I doubt not that, in a few years it may be, I shall be compelled to say that the work which I have today finished, and to which I have given so much labor is but the first glimpse of the immense creations of ancient times.” [Illustration: FIG. 31.—Restoration of _Plesiosaurus guilelmi imperatoris_ (left figure) and _Thaumatosaurus victor_ (right figure), Liassic plesiosaurs. (From E. Fraas.)]