PALAEONTOLOGY Burham. Of the porbeagle sharks the existing genus Lamna is repre- sented by L. appendiculata in the Lower Chalk, Chalk-marl and Gault of the county, L. semiplicata at Charing and Rochester, and L. sulcata at Rochester ; and the extinct Odontaspis by O. mantelli at Burham, Charing, Dover, Gravesend and Greenhithe, and O. angustidens at Dover and Hailing, neither of these species being typically Kentish. Finally, the broad-toothed sharks of the Cretaceous genus Gorax are represented in the county by remains of the widely spread C.fakatus, which have been recorded from the Chalk of Bromley, Greenhithe, Margate and Maid- stone. Among the chimsroid fishes a lower jaw in the British Museum believed to be from Kent has been described as Ischyodus incisus, but the generic reference is open to some degree of doubt. In the allied genus Edaphodon the species E. mantelli, typically from Sussex, is also known from Burham, Charing and elsewhere in Kent, and the Sussex E. agassizi is likewise recorded from Burham. The Sussex Elasmodectes ivilletti is also known from Burham. The fringe-finned ganoids are represented in the Lower Chalk of Dover and Maidstone by the well known Macropoma mantelli, a species first described from Sussex. In the sturgeon group the existing family Polyodontidce is represented by the genus and species Pholidurus disjectus, described by Dr. Smith Woodward on a fragment of the tail from Gravesend in the collection of the British Museum. Quadrangular polished scales of the general type of those of the ganoid Lepidotus in the same collection from the grey Chalk of Folkestone have been provisionally assigned to that genus with the name of L. pustulatus. Among the allied pycnodont ganoids a speci- men in the British Museum of the lower dentition from Hailing has been made the type of Ccelodus Jimbriatus, while the continental Pycno- dus (?) scrobiculatus is represented in the same collection by the palatal dentition from Charing. In another group of ganoids — the Eugnathidce — the genus and species Neorhombolepis excelsus have been established by Dr. Smith Woodward on the evidence of a specimen from Hailing, while a Burham ichthyolite has been made the type of N. punctatus. To the same family belongs Lophostomus dixoni, typically from Sussex, but also known in the Maidstone Chalk. The spear-like teeth of the widely spread Protosphyrcena ferox occur at Burham, Cuxton and else- where in the county, and those of P. minor at Burham ; a third species, P. compressirostris, has been founded by Dr. Smith Woodward on the evidence of a beak in the British Museum from the Kentish Chalk. In another family of long-beaked ganoids, the Aspidorhynchidce, the Sussex fish Belonostomus cinctus is known in Kent by remains from Burham. Passing on to the herring-like fishes of the family Elopidce, we find the genus and species Elopopsis crassus typified by remains in the Brigh- ton Museum from Mailing, and also represented by a Kentish specimen in the British Museum. In another genus of the same family (typified by the Sussex O. lewesiensis) we have Osmeroides levis described on the evidence of remains from Burham. A third genus of the family has a 39
