The history of this gigantic rodent began to be written in 1809, when M. Gothelf Fischer described a skull from a sandy deposit on the borders of the Sea of Azof, to which he gave the name of Trogontherium. Since then, at varying intervals, to the present time, new chapters have been added to this history by both Continental and British workers, describing specimens of a more or less fragmentary character which have from time to time been discovered. The English specimens have been chiefly obtained from the ‘Cromer Forest Bed,’ that rich and remarkable series of beds occupying a position in time between the Crags and the Glacial deposits of East Anglia. The ‘Forest Bed’ specimens were first made known by Sir Charles Lyell in 1840, but were more fully described by Sir R. Owen in 1846 and referred to Fischer's Trogontherium Cuvieri. It will not be necessary at this time to refer specifically to each of the additions to our knowledge of this animal or to detail the varying opinions as to affinities and nomenclature, as these particulars will be found in the Memoirs of the Geological Survey of the United Kingdom. Although most of the British specimens of Trogontherium Cuvieri have been found in the ‘Cromer Forest Bed’ a few examples have been met with in the Norwich and Weybourn Crags. The smaller species, which has been called T. minus, was obtained from the nodule bed below the Red Crag of Felixstowe, and an incisor tooth from the Norwich Crag was referred to the same species.