53 ] 
RECORDS OF W.A . MUSEUM. 
Krefft states 1 with reference to Prof. Owen’s determinations 
“ though he figures the small tubercular premolars with the nail 
headed crowns right enough.” 
The large upper premolars (Plate vi., fig. 3) has the typical 
outline ; it is slightly grooved vertically on the outside as well as the 
inside, the ridges becoming somewhat inflated towards the base. 
The enamel is worn down obliquely, particularly at the posterior 
region where the dentine is exposed ; the worn surface is on the 
inner side of the tooth. 
As is usually the case in 7 hylacoleo, the small, obliquely 
denuded first molar is situated on the inner side of the posterior 
extremity of the premolar. It has suffered much more than this 
latter, being worn down to the root on its inner surface ; the tooth 
is clearly the last of the upper cheek series. 
The first teeth in the mandibular series are the incisors ; of 
these, one, the right of a fairly young animal (plate vm., fig. 4), 
and another, the left of an older individual (plate vm., fig. 5, 6 and 
y), are fairly perfect. Like all the other teeth from Balladonia, 
they are smaller than those figured by Prof. Owen. The right 
incisor has its posterior surface rather more curved than Prof. 
Owen’s figures ; it has the same number of serrated strengthening 
ridges, but the point of the tooth is considerably worn, so that an 
oblique, roughly circular patch of dentine about 4mm. in diameter 
is exposed. It is unlikely that the origin of this worn tip was a 
fracture. 
Krefft in his paper states' 2 : “In drawing a few of the lower 
incisors of Thylacoleo ... I noticed, to my astonishment, clear 
evidence of attrition on the inner side of several. There was no 
doubt about it, they had touched each other during the lifetime of 
the animal (as kangaroo teeth do), but generally at the tips only. 
In one specimen, however, the surface of the inner side was 
observed to be quite smooth to the extent of one inch on the lower 
margin. The ridge so prominent in young or immature specimens 
has totally disappeared, and my supposition that the jaws were 
loosely attached is clearly borne out.” No other authority appears 
to have referred to this feature. 
1 Loc. cit. . p. 172. 
2 Krefft. Ann. and Mag. Nat. Hist., Series 4, Vol. X., 1872, p. 181. 
