The visitor to the geological collection at South Kensington will find a splendid series of the fossilised remains of long-necked sea-lizards. They were mostly obtained from the Lias formation of Street in Somersetshire, Lyme-Regis in Dorset, and Whitby in Yorkshire. Those from the Lias are mostly small, about eight to ten feet in length. But in the rocks of the Cretaceous period, which was later, are found larger specimens. There is a cast of a very fine specimen from the Upper Lias on the wall of the east corridor (No. 3 on Plan) of the geological galleries at South Kensington, which is twenty-two feet long. But some of the Cretaceous forms, both in Europe and America, attained a length of forty feet, and had vertebræ six inches in diameter. The bodies of the vertebræ, or "cup-bones," are either flat or slightly concave, showing that the backbone as a whole was less flexible than in the fish-lizards. [Illustration: Fig. 8.--_Plesiosaurus macrocephalus._] It may be mentioned here that Mr. Smith Woodward, of the Natural History Museum, recently showed the writer a fossil Plesiosaur that is being set up in the formatore's shop, in the same manner that a recent skeleton might be. In this, and many other ways, the guardians of the national treasure-house are endeavouring to make the collection intelligible and interesting to the general public. Specimens of extinct animals thus set up, give one a much better idea than when the bones are all lying huddled together on a slab of rock. But it is not always possible to get the bones entirely out of their rocky bed, or matrix. Great credit is due to Mr. Alfred N. Leeds, of Eyebury, who has disinterred the separate bones of many distinct skeletons of Plesiosaurs from Oxford Clay strata near Peterborough.