BBUNIQUEL, AND ITS OBGANIC CONTENTS. 
545 
less inequality of extent between the false and true molars than in the striped Zebras 
and Asses. The inner lobule, m, is antero-posteriorly extended, chiefly backwards ; it is 
not so thick transversely, not so prominent beyond the termination o of the lobe d, in^> 3, 
as in the Horse. The external longitudinal channels are more regularly concave than 
in the Horse’s jaw figured. 
I am disposed to regard the affinities of this Cave-Equine, as indicated by the charac- 
ters of the upper molar series, as nearer the E. caballus than the other existing species. 
It has belonged to a smaller variety than the present average-sized horses ; suggesting 
an animal about the size of a Spanish genet, or a pony of 13^ hands high. 
By reference to the Table of Admeasurements, p. 552, it will be seen that the molar 
series of the smaller variety of Equus caballus differs only by one line in longitudinal 
extent from that in Bukchell’s Zebra. 
The specimen of this Zebra here compared is of a mare ; and the same sexual condi- 
tion may also relate to the size of the teeth in the Cave-Equine compared (Plate LX. fig. 2). 
The first grinder, p 2, in Equus sqpelceus has the anterior lobule, a!, shorter, and the in- 
ternal lobule, m, a little longer, in proportion to its breadth, than in the Horse. The two 
outer ridges, n, r, are less prominent ; the outer concavities, f f, are less deep ; but these 
may relate to the greater degree of attrition of the crown in the Cave-species. In the 
four succeeding molars, the inner lobule, m , in Equus sjpelceus, shows a longer and more 
angular grinding-surface, i. e. the fore-and-aft diameter of this surface is proportionally 
greater, e. g. than in the E. Burchelli. This diameter prevails over the transverse one 
in m2 and m 3. The grinding-surface of m 3 is rather longer in Equus spelceus than 
in Equus Burchelli , and chiefly through the greater extension backward of the two 
posterior lobes ; the transverse breadth of the tooth is not increased in the same pro- 
portion. 
The upper molar series of the second variety of Cave-Equine (Plate LX. fig. 3) indi- 
cates a larger animal than the preceding. The disposition of the series of teeth pre- 
sents a greater curvature, in this respect resembling the Zebra (Plate LX. fig. 1), a resem- 
blance which is repeated in the shape and relative size of the last molar, m 3. But in 
the proportions and configuration of the premolars the present Cave-fossil very closely 
agrees with Equus caballus (Plate LVII. fig. 1). The ridge, n, and grooves, //', in^? 3, 
closely adhere to the pattern shown in the same tooth of the Horse (Cut, fig. 4). In q> 4 
the ridge becomes less flattened, and the channels more regularly curved. In m 1 and 
m2 of the Cave-Equine the postero-external channel,/', wants the boundary given by 
the outward production of the postexternal angle of the tooth in E. caballus (Plate 
LVII. fig. 1, m 1, m 2) ; the lobule m is more deeply impressed on the inner side. But 
the chief distinction is in the minor proportions and more simple structure of the hinder 
half of m 3. 
Compared with the Ass (Plate LVIII. fig. 1) the molar series of Equus sqgelceus (Plate 
LX fig. 3) shows the larger size of the latter animal, and also the greater antero-pos- 
terior extent of the lobule m. The non-extension outward of the postexternal angles 
