132 Royal Society. 
It has not yet been proved to have existed in Europe anterior to the 
deposit of the Boulder Clay. The second species, the R. megarhinus 
of M. de Christol, characterized by its slender limbs and the absence 
of the “cloison,”’ has been determined by the author among re- 
mains from the brick-earths occupying the lower part of the 
Thames valley, and from the Preglacial forest-bed of Cromer. The 
species ranged from the Norfolk shore southwards through Central 
France into Italy. In France and Italy it characterizes the Pliocene 
deposits, being found in the former country in association with 
Mastodon brevirostris and Halitherium Serresti, in the latter with 
M. Arvernensis. From its southern range we may infer that the 
megarhine species was fitted to inhabit the warm and temperate 
zones of Europe, just as the tichorhine was peculiarly fitted for the 
endurance of an Arctic winter. _ 
The third species is the RR. etruscus of Dr. Falconer, confined to 
the forest-bed of the Norfolk shore, and, like the R. megarhinus, 
found in the Pliocenes of France and Italy; it ranged across the 
Pyrenees as far as Malaga, and is the only species known to occur in 
Spain. 
The fourth, the R. leptorhinus of Professor Owen, is the equivalent 
of the R. hemitechus of Dr. Falconer. It is defined as “ R. a narines 
demicloisonnées,”’ and is probably not the same animal as the R. 
leptorhinus or “ R. & narines non-cloisonnées”’ of Baron Cuvier, the 
evidence as to the absence or presence of the cloison in the type of 
the species being of the most conflicting nature. In Central France 
it is identical with R. mesotropus and R. velaunus of M. Aymard, 
the R. dymardi of M. Pomel, and the R. leptorhinus (du Puy) of 
M. Gervais. Its dentition is characterized by the presence of the 
third costa in the upper molar series, coupled with the stoutness 
of the cingulum, the suppression of the anterior combing plate, the 
smoothness of the enamel, and the extent to which the upper molars 
overhang the lower, which causes the enamel on the outer side of 
the latter to be worn obliquely. The lower molars can be deter- 
mined by the flattening of the anterior area, coupled with the fine 
sculpturing of the enamel-surface. In common with the other 
fossil British Rhinoceroses, it possessed a molar series of six only on 
either side, and was bicorn. It ranged through England, from the 
Hyzena-den of Kirkdale in Yorkshire in the north, as far south as 
the plains of Somersetshire, and as far to the West as Pembroke- 
shire. It is very generally found in association with Elephas anti- 
quus and Hippopotamus major, both species which lived in Pliocene 
times. The association in Wookey Hole Hyzena-den with Hlephas 
primigenius and R. tichorhinus and other characteristic Postglacial 
mammals proves that it coexisted with the tichorhine species, to 
which it probably bore the same geographical relation as the Elk 
does to the Reindeer in the high northern latitudes. The sum of 
the evidence proves that it was coeval with the Mammoth and 
tichorhine Rhinoceros, and does not characterize deposits of an 
earlier epoch in the Pleistocene. It has not as yet been found in 
Preglacial formations. The R. leptorhinus is more closely allied to 
the bicorn Rhinoceros of Sumatra than to any other living species. 
