RHINOCEROS 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 Merckii. 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 0°225 
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 
