38 
MOLAE TEETH AND OTHEE EEMAINS OF MAMMALIA. 
of the second, are broken away : at the anterior extremity of the fragment is 
seen the hindmost barrel of the last premolar, which has never been in func- 
tional use. 
The teeth are implanted obliquely in the jaw, so that a line drawn across the 
teeth at right angles to its longer axis forms nearly an angle of 45° with the long 
axis of the jaw. The outer surfaces of the barrels are sharp in the middle, and 
slope away slightly from the base towards the inner side ; the median valley which 
separates the two barrels is deep, and extends downwards almost to the base of the 
crown. 
The hindmost surfaces of the outer halves of the barrels are somewhat concave. 
Along the whole of the outer portion of the teeth there is a well-defined and 
conspicuous cingulum ; this is most marked on the anterior and posterior surfaces ; 
it becomes slighter on the external surfaces of the barrels, and on the surfaces 
between tlie two barrels ; on the anterior surfaces of the teeth the cingulum is 
raised into a number of points. In the median valley, which divides the barrels, 
there is a large pointed tubercle, blocking the entrance to the valley ; the valley 
itself is narrow and becomes shallower as it passes inwards. The whole of the 
enamel for the outer half of the crowns is corrugated and roughened like that of 
Sivatherium. 
On the crown surface the postero-internal angle of the anterior barrel {middle 
of upper border figure) forms the most prominent point on the inner side of the 
tooth ; while the antero-internal angle is the least prominent point on this border. 
The central enamel folds of the crown are long and narrow, and they wmuld not 
form complete islands until the tooth became considerably worn dowm. The outline 
of the inner border of the teeth is the same as in tlie molars of Camelopardalis ; 
and the late period at wdiich the folds of enamel on the crown become insulated 
is also a point common to the teeth of the two genera. 
On the inner surface (/z^. 1) we are enabled to see the forms of the costse from 
the contiguous unbroken lobes of the two molars : on the anterior half of the second 
lobe there are three costae, of which the median is the highest ; the posterior and 
anterior costae are of nearly equal height, the posterior being the most prominent ; 
the anterior costa leads downwards into a kind of cingulum, bordering the anterior 
edge of the tooth ; a deep channel, not extending to the base of the crown, divides 
the anterior from the posterior lobe of the inner surface. 
The inner surface of the hinder lobe has likewise its highest point on the 
middle line, but there is only a very slight costa on this line ; the posterior angle 
shows the extremity of the central enamel fold of the crown, forming a fissure on the 
inner surface of the tooth. 
At the base of the internal surface of the molars the rugosity of the enamel 
has almost disappeared ; higher up this rugosity reappears, but it is nowhere so 
much developed as on the outer surface. 
( 56 ) 
