RHINOCEROS TICHORHINUS. 341 
Rhinoceros of nearly the same age as that from Lawford ; 
the summit of the second crescent of the fourth premolar 
shows that it had just come into use at the period when 
the animal perished. The anterior of the three ridges, on 
the inner side of the crown of the third and fourth pre- 
molars, supports a small oblong tubercle,* a variety not 
present in the Lawford specimen. In the Rhinoceros lepto- 
rhinus of the fresh-water deposits in Lombardy, a species 
also co-existing of old with the tichorhine Rhinoceros in 
Britain, the premolar teeth extend forwards much closer 
to the anterior end of the jaw, and the second premolar 
is placed in advance of the posterior border of the sym- 
physis (see figs. 132 and 134). 
The portion of lower jaw, with two molar teeth, 
which forms the subject of the first plate in Douglas’s ‘ Dis- 
sertation, and the foundation of much ingenious reason- 
ing, on the supposition that it was part of a Hippopotamus, 
belongs to a Rhinoceros, and probably to the extinct 
tichorhine species. It was discovered in ‘‘a stratum of 
drift or river sand, blended with a kind of clay, of a 
yellowish grey tinge,” at the depth of twelve feet, in dig- 
* Cuvier, in detailing the discovery at Avary of certain fossils, which he refers 
to the Rhinoceros incisivus, says, “ Enfin une dent inférieure, plus usée, est peut- 
étre la cinquiéme ou la sixiéme ; j’y vois, au deuxieme croissant du coté interne, 
un crochet que je ne retrouve pas dans les autres espéces.” ‘ Ossemens Fossiles,” 
1822, tom. iii. p. 391. M. Christol, believing that he had discovered this 
character in the molars of the lower jaw of the Zthinoceros tichorhinus, regards 
it as distinctive of that species. ‘Annales des Sciences,’ 1835, tom. iv. p. 62. 
In the lower molar tooth, which he figures to illustrate this character, it is 
shown as a minute notch near the upper and posterior part of the middle ridge 
on the inner side of the crown, which ridge is formed by the posterior and 
inner termination of the first or anterior crescent ; the notch cuts that ridge in 
a direction downwards and forwards, detaching from it a small conical process. 
I cannot find a trace of this character in any of the lower molars of the 
Rhinoceros tichorhinus which I have examined ; and I have especially compared 
with the figure given by M. Christol, loc. cit., pl. ii. fig. 1, a molar, the fourth, 
of the same size and with the same degree of usage. Such small tubercle, 
notch, or crochet, wherever developed, is most probably an accidental variety. 
