RODKNTIA. 61 



Mr. E. 0. Moor, of Great Bealings, has a fine upper premolar 

 from the Red Crag of Newbourn, and there are two cheek 

 teeth in the Canham collection, Ipswich Museum, Castor 

 reterior is only known from the Red Crag Nodule-bed of Suffolk. 



Genus TKOGONTHERIUM, Fischer. 



Trogonti-ieeium Cuvieei, cuvier {Fjscseb, MS.). 



(Vert. Forest Bed, Plate XI.). 



The specimen on which this genus was established by 

 M. Gothelf Fischer (Mem. Soc. Imp. Nat. Moscow, Vol. II., 

 p. 260, 1809) was found in a sandy deposit near Taganrok, on 

 the borders of the Sea of Azof. When Trogontherium was 

 described no specific name was given to it, and after a prolonged 

 search I have been unable to find that Fischer ever used the 

 specific name of T. Guvieri, although Cuvier attributes the name 

 to him (Ossem. Foss., Nouvelle edit., 1823, Vol. V., p. 59), giving 

 as a heading to Article III., " Des Castors des terrains meubles, 

 et notamment de la grande espfece nomm^e Trogonthsrium 

 Guvieri, par M. de Fischer." Notwithstanding this heading, 

 Cuvier called this rodent Castor trogontherium. 



The presence of Trogontherium Guvieri in the Forest-bed of 

 Norfolk was first noticed by Sir R. Owen (Brit. Foss. Mamm., 

 p. 184, 1846), and its intricate synonymy is given in the Survey 

 Memoir (Vert. Forest Bed, p. 65, 1882), together with an account 

 of the osteology, as far as known, and of the peculiar variations 

 undergone by the patterns of the teeth during wear ; which vari- 

 ations had led to the British specimens being referred to a distinct 

 genus and species. A skull of this rodent, lately obtained by Mr. 

 A. Savin from the Forest-bed of East Runton, still further 

 confirms Sir R. Owen's opinion of the specific identity of these 

 British specimens, and the Trogontherium Cuvieri of Fischer. 



In Britain T. Guvieri is essentially a Forest-bed species, 

 most of the specimens being from that horizon ; but fragments 

 have been found in the Weybourn Crag at E. Runton and in 

 the Norwich Crag of Thorpe. On the Continent it is known 

 from the Pliocene of Saint Prest, under the name of Conodontes 

 Boisvillettii. 



TeOGONTHBEIUM minus, NEWTON. 



Plate V., Fig. I7a, h, l&a, b, c. 



A small Trogontherium maxilla from the Nodule-bed of the 

 Red Crag of Felixstow,* in the possession of Mr. E. C. Moor, 

 has received the name of T. minus (Quart. Journ. Geol. Soc, 



* Not from near Woodbridge as stated in original description. 



D 2 



