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 A HISTORY OF KENT Catalogue of Fossil Birds. Among these the one known as Lithornis vulturimis is represented by fragments of the skeleton, and is believed to be one of the birds of prey. Argillornis longipinnis, on the other hand, appears more nearly allied to the gannets, and had a spread of wing fully as great as an albatross. A skull recently described by Dr. C. W. Andrews ^ as Prophaethon shrubsolei (appropriately named in honour of Mr. W. H. Shrubsole, the enthusiastic collector of Sheppey fossils) may perhaps be regarded as indicating an ancestral type of tropic-bird {Phaethon). More remarkable is Odontopteryx toliapica, a genus and species named on the evidence of an imperfect skull in which the jaws are strongly serrated, these serrations being in the bone itself and having nothing to do with true teeth. Probably this bird was distantly related to the gannet group {Stegampodes). Another type is Halcyornis toliapicus, originally described from a small skull which was supposed to show affinity to the kingfishers. Judging however from a wing-bone provision- ally assigned to the species, its relations seem to be with the gulls. Lastly, Dasornis londiniensis is known by a portion of a skull from Sheppey, which indicates a bird of the approximate size of an ostrich. Although the affinities of this gigantic bird are still problematical, it was apparently related to Gastornis klaaseni, known by some limb-bones from the Lower Eocene strata of Surrey. Of the reptiles from the London Clay of the county all but three belong to the chelonian order (tortoises and turtles) ; the exceptions being a crocodile and one or two serpents. The crocodile [Crocodilus spenceri) is a long-snouted species typified by a skull from Sheppey in the collection of the British Museum ; it has received two other names, C. toliapicus and C. champsoides. The snakes from this formation indicate a distinct family [Palceophida), and were probably of marine habits. The typical Palceophis toliapicus, which seems to have attained a length of from ten to twelve feet, was described upon the evidence of vertebrae from Sheppey, but is also recorded from the Middle Eocene beds of Sussex. The larger P. typhceus, on the other hand, is typically from Sussex, but apparently also occurs at Sheppey. Among the tortoises and turtles from the Kentish Eocene, the existing soft tortoises [Trionychidce), characterized by their sculptured shells, devoid of horny shields, are represented by Trionyx pustulatus, a species described on the evidence of a single plate of the upper shell from Sheppey. Another plate from the same locality, in the British Museum,* apparently indicates a second Kentish species of the genus. The soft tortoises are now confined to the warmer regions of the globe, where they are widely spread ; and their presence at Sheppey is indicative of the tropical or subtropical nature of the Lower Eocene fauna. Among the marine turtles, or Chelonidce, the extinct genus Argillochelys is typified by specimens from the London Clay of Sheppey, in which formation ^ See Cat. Foss. Rept. Brit. Mus. iii. 21 ; in the same volume will be found descriptions of the other Sheppey chelonians. 34
 * Proc. Zool. Soc. London, 1899, p. 776.