544 
PROFESSOR OWEN’S DESCRIPPION OF THE CAVERN OF 
to the grinding-surface, the proportion will be that shown in the Ass (Plate LVIII. fig. 1, 
m 3). 
The antero-external angle in p 3 and m 2 is thicker and more indented than in the 
foregoing Equines. The lobule m is relatively smaller and less produced from before 
backward than in the Horse — the Zebra in this respect resembling the other striped 
Equines and the Asses, as it does in the greater antero-posterior extent of the grinder, 
compared with its breadth. The lower grinders of the Zebra show no differences from 
those of the Dauw worth figuring. 
Some characters distinctive of Equidce may be noted in the part of the jaw and teeth 
anterior to the grinders, the relative extent of this part to the molar series varying in 
different species. Thus, measured from the fore part of p 2 to the front margin of the 
incisor i 1, the extent in the upper jaw of the Horse equals p 2 to m3 inclusive, less 
one-third of that molar (m 3) ; in the Kiang it equals p 2 to m 3, less two-thirds of m 3 ; 
in the Ass it equals p 2 to m 2 inclusive ; in the Quagga it equals p2 to m2 inclusive, 
less one-third of m 2 ; in the Dauw it equals^? 2 to m 2, less one-half of m 2. There is a 
corresponding difference in the relative extent of the diastema, from p 2 to the alveolar 
border of i 3, to the extent of the molar series ; thus the diastema equals in the Horse 
p 2 to m2 inclusive, less three-fifths of m 2 ; in the Kiang p 2 to m 1 inclusive, less one- 
eighth ; in the Ass p 2 to p 4, less one-fifth ; in the Quagga p 2 to p 4, less one-fourth ; 
in the Dauw p 2 to p 4, less one-tenth. 
Thus the relative extent of the diastema is greatest in the Horse, least in Quagga. 
The canine tooth is nearer the middle of the diastema in the upper jaw of the Horse than 
in the smaller Equines, especially the Ass. 
The incisors appear to be relatively larger in the striped Equines than in the Ass, 
Kiang, and Horse. 
Comparison of the teeth of Equus spelaeus with those of existing Equines. 
Having offered these preliminary remarks, with the requisite illustrations of the denti- 
tion of most of the existing species of Equidce, 1 proceed to the comparisons of that of 
the Equines obtained from the Cavern of Bruniquel. 
Provisionally, for convenience of reference, I designate them as belonging to an Equus 
spelaeus. 
Of the upper grinders of such Cave-Equines, from Bruniquel, the portions of jaws 
including the entire series of those teeth indicated two varieties, as above remarked. 
The following were notable in a comparison of the first of them (Plate LX. fig. 2) 
with the corresponding part of the dentition of the Horse ( E . caballus, Plate LVII. fig. 1). 
The specimen from the Cavern is the left upper jaw. The series of teeth therein (fig. 2) 
resembles the upper molar series of the Horse in the slight degree of curvature. The 
last molar, m 3, though not so large relatively as in the Horse’s teeth figured, is not so 
small as in other recent Equines : it is as strongly bilobed behind as in Eq. caballus. 
The outer longitudinal ridge, n, is moderately thick and indented (in p 3). There is 
