. Bulletin of the British Museum (Natural History), Geology. 3i6 BRITISH WEALDEN SHARKS (Text-figs. 14, 15c) lateral, and shallow teeth with a weak labial process are probably posterior (Text-fig. i6b). At lower horizons there is no difficulty in distinguishing between L. breve breve and the other subspecies of the species, but at higher horizons, the Weald Clay of Henfield and the Perna Bed in the Atherfield Clay, examples occur in which there are weak accessory cusps (Text-fig. i6c) or lateral cusps (Text-fig. i6a, d). These specimens tend towards L. breve pustulatum, to which most of the Pe
. Bulletin of the British Museum (Natural History), Geology. 3i6 BRITISH WEALDEN SHARKS (Text-figs. 14, 15c) lateral, and shallow teeth with a weak labial process are probably posterior (Text-fig. i6b). At lower horizons there is no difficulty in distinguishing between L. breve breve and the other subspecies of the species, but at higher horizons, the Weald Clay of Henfield and the Perna Bed in the Atherfield Clay, examples occur in which there are weak accessory cusps (Text-fig. i6c) or lateral cusps (Text-fig. i6a, d). These specimens tend towards L. breve pustulatum, to which most of the Perna Bed teeth belong, and also towards L. selachos Estes, from the Upper Cretaceous of America (see p. 330). Lonchidion breve crenulatum sp. et ssp. nov. (Text-figs. 17, 18) Diagnosis. Lonchidion breve in which the occlusal margin of the tooth crown is irregularly crenulate, and in which the lingual and labial faces of the crown are weakly and sparsely striated. HoLOTYPE. (Text-fig. 17B), tooth without root from the Paddockhurst bone-bed. Material. In addition to the holotype, twenty-five teeth, all without roots. Horizons and localities. Wadhurst Clay : Ashurstwood, Sussex. Grinstead Clay : Paddockhurst Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original British Museum (Natural History). London : BM(NH)
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