QUATERNARY FAUNA OF GIBRALTAR. 93 
that it is a second premolar of the left side (pm. 2,s). That it is not a milk-molar is 
shown by the circumstance that the opening of the median sulcus does not extend 
nearly to the bottom of the crown. The existence of an oblique descending ridge on the 
inner face of the hinder colline seems clearly to indicate its relation with the pm. 4d 
described above. inSoeims, 
Besides these more perfect teeth, there is (1) a broken fragment of a much-worn 
upper molar of small size, which, so far as can be judged, probably belonged to the 
deciduous series ; (2) amere chip from the inner face of a small much-worn premolar. 
Judging from the apparently different ages or states of wear of these teeth, it is highly 
probable that they must have belonged to at least two individuals, one of which was 
much older than the other. 
With respect to the specific characters afforded by the teeth, it may be stated that 
they seem to correspond in every particular with Dr. Falconer’s description of those of 
Rhinoceros hemitechus, as will be seen on reference to his account of that species in 
‘ Paleontological Memoirs,’ vol. ii. Without going into needless detail, I may quote 
what he says on the distinctive characters of the premolars and molar teeth of this 
species }. ‘ 
He remarks that the premolars of R. hemitechus may be characterized :— 
1. By the absence of an internal basal “ bourrelet ;” 
2. By there being only two fossettes in the worn crown; 
3. By the middle valley being traversed by the processes of a bifid crochet emitted 
from the posterior barrel, and by a parallel combing-plate given off by the outer or 
longitudinal ridge ; 
4, By being invested like the true molars with a very thick coat of cement. 
He proceeds to remark that the absence of a basal “ bourrelet,” besides other cha- 
racters, distinguishes the premolars of R. hemitechus from R&. leptorhinus and R. 
megarhinus. Since R. leptorhinus of Cuvier is synonymous with R. megarhinus of 
Christol, and R. leptorhinus of Owen with R. hemitachus, Falc., it is not quite clear 
what his meaning is in the expression just quoted. But, as partly explanatory of it, 
I may cite a note of his, made in the British Museum in June 1864, with reference to 
a tooth numbered 36770, which runs thus :—‘ A true right from Peckham, exactly in 
the same stage of wear of crochet and outer ridge as the Gibraltar molar; and the ter- 
mination of the transverse valley, as in it, is a triangular fissure without complication. 
It hasno basal ‘ bourrelet.’. It is probably m. 1, like the Gibraltar tooth; and the two 
are of nearly the same size. It has no combing-plate.” Dr. Falconer, in a side-note, 
says that this tooth “ ought to be figured with the Gibraltar bone,” thus marking 
emphatically, what I know was his opinion, that the two teeth were specifically 
identical; and his recommendation as to the giving of a figure of the Peckham tooth 
should have been obeyed, had the necessity for it not have been obviated by the 
1 Op. cit. p. 328, pls. xvi., xvii. ke. 
VOL. X—PART Ul. No. 6.—August 1st, 1877. ) 
