The correspondence and controversy elicited by the statement of Captain M’Quhæ were exceedingly interesting. It is noteworthy, at the outset, that few, perhaps none, who had read the original statement, suggested the idea of illusion, while it need hardly perhaps be said that no one expressed the slightest doubt as to the _bona fides_ of Captain M’Quhæ and his fellow-witnesses. These points deserve attention, because, in recent times, the subject of the sea-serpent has been frequently mentioned in public journals and elsewhere as though no accounts of the creature had ever been given which had been entitled to credence. I proceed to summarise the correspondence which followed M’Quhæ’s announcement. The full particulars will be found in Mr. Gosse’s interesting work, the “Romance of Natural History,” where, however, as it seems to me, the full force of the evidence is a little weakened, for all save naturalists, by the introduction of particulars not bearing directly on the questions at issue. Among the earliest communications was one from Mr. J. D. M. Stirling, a gentleman who, during a long residence in Norway, had heard repeated accounts of the sea-serpent in Norwegian seas, and had himself seen a fish or reptile at a distance of a quarter of a mile, which, examined through a telescope, corresponded in appearance with the sea-serpent as usually described. This communication was chiefly interesting, however, as advancing the theory that the supposed sea-serpent is not a serpent at all, but a long-necked plesiosaurian. This idea had been advanced earlier, but without his knowledge, by Mr. E. Newman, the editor of the _Zoologist_. Let us briefly inquire into the circumstances which suggest the belief.