TROGONTHERIUM CUVIERI. 185 



than the European species, which itself surpasses in size the 

 Beaver of North America. The length of the Siberian skull, 

 from the occipital ridge to the most convex part of the inci- 

 sors, was seven inches three lines. The chief difference 

 which Cuvier recognized in the drawing was in the pro- 

 portion of the last molar tooth of the upper jaw, which 

 was longer, instead of being, as in the Beaver, shorter than 

 the rest. 



The first indication which presented itself to me of the 

 Trogontherium as a British fossil, was from a fine speci- 

 men of the incisor of the lower jaw in John Hunter's Col- 

 lection of Organic remains in whose manuscript catalogue 

 it is described as "a long cutter of the Scalpris-dentata, or 

 Glires genus, from Walker's Cliff, Norfolk. 11 This tooth 

 measures five inches and a half in length, and must have 

 exceeded six inches when perfect, but it has suffered mu- 

 tilation at both ends. 



The chisel-crowned incisor in the lower jaw of the Tro- 

 gontherium (fig. 71) measures seven inches, following the 

 outer curve from the root to the abraded summit. This 

 magnificent relic of the gigantic Beaver, which is now in 

 the British Museum, was discovered by the Rev. Mr. Green, 

 of Bacton, in that interesting lacustrine formation, with 

 the submerged forest, which is noticed at p. 25 : it was 

 taken out of the bed of reddish sand which, at Ostend, 

 has been spread immediately over the chalk. The in- 

 cisive tooth is longer and stronger in proportion than in the 

 existing Beavers, and doubtless operated with proportional 

 effect upon the members of that ancient forest when they 

 were green and flourishing. The projection of the crown, 

 or exposed part of the incisor, is such, that the distance 

 between its summit and the anterior border of the first 

 molar is as great as from this part to the articular con- 



