RHINOCEROS IIEMITCECIIUS. 347 



their other dental characters. Cuvier, in describing the 

 lower jaws of his species ' a narines non-cloisonees' of Italy, 

 refers to figs. 8 and 9 of PI. IX., representing- Tuscan speci- 

 mens, in proof that it had seven molars below in the adiilt 

 state, the pre-antepenultimate or first premolar, which is 

 suppressed in the Siberian Rhinoceros, being developed ; 

 and he seized upon this character as a distinctive mark of 

 his RMn. leptorhinus. This pre-antepenultimate, although 

 present in the milk dentition, is suppressed in llliin. hemi- 

 toechus in the adult state, and it is also wanting in RMn. 

 megarhinus. Thence, it becomes a point of the highest 

 interest to ascertain, whether it was present or suppressed 

 in the fossil Rhinoceros of the ' Elephant-Bed ' of Happis- 

 burgh. Professor Owen has described (Brit. Fos. Mam., p. 347) 

 a fine specimen, comprising the greater portion of the hori- 

 zontal ramus of the lower jaw of a Rhinoceros, procured from 

 the ' Lignite Bed ' of Cromer, being an extension of the Hap- 

 pisburgh deposit. In this fragment, which is of a young adult, 

 'there were four premolars and three true molars. Of the 

 latter, two are in place, and the last emerging ; of the former, 

 the alveoli of the first remain, the two next are in place, and 

 the fourth or last is embedded in the jaw under the last milk 

 molar, which had not yet been shed. A portion of the wall of 

 the jaw has been excised, and the milk tooth is seen super- 

 imposed to its successor. The pre-antepenultimate premolar 

 in this case had dropt out, but the fang-pits prove beyond 

 question that it had been there. Professor Owen has selected 

 this specimen as a standard example of RMn. tichorMnus, for 

 comparison with a corresponding jaw of his RMn. l&ptorhinus, 

 and he has given measurements of the two in contrast. I 

 have seen the specimen in question, in Mr. R. Pitch's col- 

 lection in Norwich, and both the form of the jaw and the 

 relative proportions of the teeth conveyed to my mind the 

 impression that it belonged neither to RMn. tichorMnus nor 

 to RMn. hemitoechus, but to the same species as the specimens 

 above described, of Messrs. Gunn and Layton, i.e. to the 

 ' Rhinoceros a narines non-cloisonees ' of Cuvier, from Tus- 

 cany. Not having the fragment now before me, I am 

 desirous of expressing this opinion with diffidence and reserve. 

 Professor Owen was probably influenced, in arriving at 

 the above identification, by the belief that he had established 

 the fact that the first premolar is present in the lower jaw 

 of RMn. tichorMnus, although Cuvier had asserted the con- 

 trary. In the ' British Fossil Mammalia ' he has given a 

 representation, natural size (fig. 137, p. 363), of the two 

 anterior teeth of a young fossil jaw from Lawford, preserved 

 in the Oxford Museum. These teeth he considers to be pre- 



