The attempt to classify these presents difficulties. Mr. Gosse, however, has very ably reviewed the somewhat scanty materials at his command, and, agreeing with the suggestion made originally by Mr. Newman, has elaborated the argument that one of the old Enaliosaurs exists to the present day. This form, Palæontology tells us, commenced in the Carboniferous, attained its maximum specific development in the Jurassic, and continued to the close of the Cretaceous periods. This rational suggestion is supported by the collateral argument that some few Ganoid fishes and species of Terebratula, have continuously existed to the present time; that certain Placoid fishes, of which we have no trace, and which consequently must have been very scarce during Tertiary periods, reappear abundantly as recent species; that the Iguanodon is represented by the Iguana of the American tropics, and that the Trionychidæ, or river tortoises, which commenced during the Wealden, and disappeared from thence until the present period, are now abundantly represented in the rivers of the Old and the New World. The points of resemblance between the northern and most often seen form of the sea-serpent and certain genera of the Enaliosaurs, such as Plesiosaurus, are a long swan-like neck, a flattened lizard-like head and progress by means of paddles. A difficulty in this connection arises, however, in respect to the breathing apparatus. Palæontologists favour the idea that the Plesiosaurus and its allies were air-breathing creatures with long necks, adapted to habitual projection above the surface. Such a construction and habit is, as I have before said, to my mind, impossible in the case of an animal of so scarce an appearance as the sea-serpent; and I am incapable of estimating how far the theory is inflexible in regard to the old forms that I have mentioned. May there not be some large marine form combining some of the characters of the salamander and the saurians; may not the pigmy newt of Europe, the large salamander tenanting the depths of Lake Biwa in Japan, and the famous fossil form, the _Homo Diluvii Testis_ of Sheuzberg, have a marine cousin linking them with the gigantic forms which battled in the Oolitic seas? May not the tuft of loose skin or scroll encircling its head have some connection with a branchial apparatus analagous to that of the Amphibia; and was not the large fringe round the neck, like a beard, noticed on the one seen by Captain Anderson when in the Delta in 1861, of a similar nature?