11. Gothelf do Fischer was the first to announce the existence of the remains of an extinct animal allied to the Beaver. These remains, consisting of a fossil cranium, were discovered on the sandy horden: of the Sea of Azof. Cuvier admitted the specific distinctness of this animal, and adopted the name Castor trogoutherium. Professor Owen, in his history of British Fossil Mammals,' describes tire structure of the teeth in this animal from a specimen in the collection of John Hunter in the Royal College of Surgeons of England, which was found in Walker's Cliff, Norfolk, and from a specimen in the possession of Sir Charles Lyell found in the Norwich Crag nt Cromer. From au examination of these specimens Professor Owen was enabled to add considerably to the details of our knowledge of the structure of this animal. On this ground he proposes to constitute for this species a new subgenus, and to call it Tregontherium Curie-H. From the cha racter of the remains of the Trogontherium, Professor Owen concludes that it must have been much larger than the European Beaver. That
the European Beaver is distinct, and not the degenerate dersecirdant of the great Trogontheriunt, is proved by the fact that the remains of beavers in no respect differing either in size or in anatomical cha racters from time Castor Fiber of the present day co-existed with the Trogontherium.
Itemalns of the Common Beaver have been discovered by .N1 r. Green, in company with the extinct :Mammoth, in the lacuetrine formations at Bacton. Remains of the Beaver have also been found in the cliffs at Nundesley, and in the oyster-bed at Happisburg in Norfolk ; also in the fluvio-marine crag at Thorpe in Suffolk, and from a formation earlier still in the fluvio-marine crag at Sizewell Gap near Southwold, Suffolk. M. Fischer also received the remains of another Beaver with those of Trogontherium from near the lake of Rostbff, in the depart ment of Jarosslow, and which he called Trogontherium, IVerneri, but which Cuvier recognised as the remains of the Common Beaver.