74 TITANOTHERIUM., 
ANTERO-POSTERIOR. TRANSVERSE. 
Inches. Lines. Inches. Lines. 
Last true molar ; : P ; ; : : Paes: ® i 11 
Second true molar ; ; 5 5 4 E , Spm 2) 9 1 9 
First true molar : : : ; : : s A 1 7 
The isolated crown above mentioned of an inferior left premolar (Pl. XVI. Figs. 
8-10), probably the second, measures only sixteen lines antero-posteriorly, and 
almost an inch transversely, indicating a rapid reduction in size of the teeth from 
behind forward; nevertheless, this is gradual, for the fangs of the last premolar, 
still retained in the portion of lower jaw, on a line with the connection to their 
crown, measure twenty-one lines antero-posteriorly. The inner side (Fig. 10) of 
the specimen of the premolar is a smooth vertical plane; and externally (Fig. 9) 
the basal ridge is deep, but thin, and rises to the most prominent part of the lobes, 
as upon the true molars. The masticating surface (Fig. 8) presents a broad tract 
of dentine bordered by enamel, bilobed externally, and straight internally. 
The crown of the inferior canine (Pl. XVI., Figs. 11, 12) is curved conical in 
form, and, in section at its base, is very nearly circular. Internally, its base is 
embraced by a thick, deep cingulum, with a prominent margin, which exhibits also 
a tendency to pass around the outer side ofthe tooth. The outer (Fig. 11) and 
inner (Fig. 12) sides of the tooth are defined by a saliance of the surface, and the 
former is uniformly convex and smooth, the latter angularly convex, less broad, 
and less smooth. The enamel is worn off from the point of the tooth, and also 
below this antero-externally over an oval space almost half an inch in length, indi- 
cating that the inferior canine, as in the undoubted Pulaeotherium,’ occupies a 
position, when the mouth is closed, posterior to the superior canine. 
Measurements of the crown of the inferior canine are as follows :— 
Inches. Lines. 
Circumference at base , 5 : : 0 ; é : : Bei) 
Length of external convex surface. : ; 5 > : : ee al 7 
Height from the base internally Gee ; , : 3 3 cee 2 
Of the two fragments of upper molars above mentioned, one is the internal half 
of the crown of a premolar (Pl. XVII., Figs. 5, 6), probably the second; the other 
is an internal portion of a true molar (Pl. XVL, Figs. 6, 7). 
The former specimen measures one inch five lines antero-posteriorly, and its 
masticating surface (P]. XVIL., Fig. 5), which is very much worn down, presents 
a form intermediate to that in the corresponding tooth of Palaeotherum magnum, 
and Aceratherium incisivum. Internally (Fig. 6), the crown is transversely convex, 
and is very sloping inwardly from the fangs, so that the tooth has projected very 
considerably internal to the alveolar margin of the palate. This side of the tooth 
is formed by a thick and deep cingulum, which envelops the bases of the inner 
lobes, and exhibits an obtusely rounded margin, thickest anteriorly. 
The inner lobes, of which the anterior is very much larger than the posterior, 
are confluent, and, in the specimen, are nearly worn to their base, and present a 
1 Cuvier, Rech. sur les Ossem. Foss., éd. 3, III. 8, 9, Pl. V., Fig. 1. 
