BHINOCEROS LEPTORHINUS. 365 



teeth occupy a greater space, and that the edentulous 

 end of the symphysis Is broader than in the jaw of the 

 Rh. leptorhinus, figured by Cuvier, refers it to a distinct 

 species, which he calls Rhinoceros MercJcii. The symphy- 

 sis is not, however, entire in either of the specimens com- 

 pared, according to the figures, from which I can by no 

 means satisfy myself of their specific distinction. The 

 length of the alveolar series, from the sixth to the second 

 molar, inclusive of the specimen from Clacton (fig. 133), 

 is 0'205 in French millemetres, or eight and a quarter 

 inches English ; in the Italian specimen, and also in that 

 from the Rhine, if Dr. Kaup^s figure be, like Cuvier's, 

 one-fourth the natural size, the same dimension gives O225 

 millemetres, or nine inches : but different specimens of 

 the lower jaw of the Rhinoceros tichorhinus have presented 

 as much variety of size. I conclude, from the foregoing 

 comparisons, that the lower jaw of the Rhinoceros from 

 the Rhenish deposits, as well as that from Essex, are 

 specifically identical with the lower jaws from Tuscany, 

 which Cuvier has referred to his Rhinoceros leptorhinus. 



But what are the characters of the rest of the cranium, 

 and in what degree do the proportions of the nasal bones 

 accord with the name imposed upon the species which 

 the lower jaw incontestably proves to be distinct from 

 all other species known at the period of its first descrip- 

 tion ? M. Christol has shown that the answers given 

 to these questions on the authority of the cranium dis- 

 covered by M. Cortesi are unsatisfactory. No portion of 

 the upper jaw or cranium was associated with the Rhenish 

 specimen of the lower jaw of the Rhinoceros leptorhinus 

 described by Dr. Kaup. But the discoverer of the corre- 

 sponding portion of the same species in our own fresh- 

 water deposits was so fortunate as to obtain, by his own 



