221—44 INDIAN TERTIARY AND POST-TERTIARY YERTEBRATA. 
size, in figure lc of the first-mentioned plate ; and, of three-fourths the natural size, 
in figure 2 of the second plate. The dentition is also figured from the lateral and 
palatal aspects, of one-third the natural size, in plate CXXXI. of Prof. Owen’s 
“Odontography.” In figure 5 of plate XXX. of the present volume the dentition 
of the left side (the canine having been restored from the opposite side) is figured 
from the palatal aspect, of the natural size. 
In this specimen the carnassial ( pm. 4 ) and the two true molars are perfect on the 
left, and but slightly damaged on the opposite side. Both canines are present, that 
of the right side being nearly perfect. The 1 alveoli of the premolars and incisors 
are distinct, although the teeth themselves have dropped out. “ The only consider- 
able deficiencies are in the posterior and lower part of the occiput, both zygomatic 
arches, and in the lower end of the nasals,, where a fissure extends across the face on 
both sides towards the orbits.” 
The incisors, as indicated by their alveoli, were six in number, and the external 
pair were larger than the others, as is usual in the family. The canines are of huge 
size, and present a sub-oval section : the right canine is worn down at the apex, 
indicating that the skull belonged to an aged animal. The antero-posterior diameter 
of its base is P4, and the transverse 1 inch. Behind the canine there are three 
alveoli, which are considered by Dr. Falconer to have carried the second and third 
premolars ( pm. 2 and pm. 3 )., the first of this series being absent, and there being no 
space for it between the canine and pm. 2 . This view implies that pm. 3 , in place of 
being single-fanged as in Ursus, must have been implanted by two distinct fangs. 
The probable correctness of this view is indicated by the circumstance that in the 
lower jaw pm. 4 (biting against pm. 3 ) is proportionately larger than in Ursus ; being 
in fact so large that, as will be shown below, it was mistaken by Prof. Owen for the 
carnassial : this indicates that pm. 3 must have been a relatively large tooth. The 
occurrence of two fangs to pm. 3 in the allied American Arctotherium ( vide infra), also 
confirms this view. Uycenarctos sivalensis, therefore, differs from the true bears by' 
the suppression of pm. 1 , and the larger size of pm. 3 ; the presence of two fangs to 
the latter is a canine character, exhibited by Ceplialogale. 
The three hinder cheek-teeth present the most marked distinction from the 
corresponding teeth of Ursus. The carnassial (which in the specimen is considerably 
worn) is relatively large, and slightly exceeds the length of either of the true 
molars : in this respect it differs from the corresponding tooth of Ursus , which is 
always shorter than m. 1 ; whence Uycenarctos is classed as megalo- and Ursus as 
meionocreoclont. The blade of this tooth has posteriorly the two main lobes correspond- 
ing to those of the ursine tooth (pi. XXVIII., fig. 3), while in advance of these there 
is a talon, or another lobe, which is altogether unrepresented in the latter, and 
corresponds to the first lobe of the Hyaena’s tooth (pi. XXXV., fig. 2, pm. 4) : in 
describing this tooth in Uycenarctos it will be well to allude to this anterior division 
of the blade as a talon. The tubercular portion of the tooth is well developed, and 
