276 Ona Double-rooted Tooth from the Purbeck Beds. 
canine,” and it is subsequently added that the canine is ‘fa 
powerful tooth implanted by two stout fangs.” The tooth 
as figured (Journ. Acad. Nat. Sci. Philad. 2nd ser. vol. ix. 
pl. ix. fig. 4) does not bear out the alleged double-rooted 
character. I have accordingly made an enlarged drawing of 
this tooth, so as to compare with the tooth of Nuthetes. It is 
exposed on the inner side; the crown is enamelled at its 
summit, with ridges and a slight cinguloid thickening at the 
base of the enamel; the extremity of the root of the tooth is 
lost. I have no doubt it is channelled in the way Professor 
Osborn’s figure indicates ; but, from the impression left where 
the anterior angle of the root is lost, which appears to be that 
of the external surface of the jaw, I cannot regard it as better 
evidence of a divided root for that particular tooth, than the 
corresponding impression of a tooth of Nuthetes, already re- 
ferred to, would give for division of the roots in that specimen. 
There is a similar pit to that figured by Owen in Nuthetes 
apparently, on the external side, and a compression of the 
part of the root beyond it. In any case the evidence is not 
conclusive that the root was divided in this tooth of T’réco- 
nodon ferox, which is the only example available for exami- 
nation in this country. If the fossil gave such evidence, 
then the roots indicated would be dissimilar in form to those 
figured in the fossil tooth in the British Museum, No. 48,208. 
It is possible that a nearer comparison with the crown of that 
fossil might be found in Plagiauiax medius (Owen), but no 
one has yet affirmed that the roots of the tooth are divided in 
that genus. 
It was from considerations of this kind that I judged, 
when originally comparing the specimen with the teeth 
of Purbeck Mammalia, that there was no sufficient ground 
for discussing the question of it being possibly mam- 
malian. And now, having figured the evidence for such a 
coniparison, it must be left to future discovery to determine 
whether the tooth, which has the mammalian character of 
two roots, can be identified as a Mammal, or whether it must 
still be regarded as an abnormal form of a tooth ot Nuthetes 
destructor. If the evidence for the double-rooted canine in 
the Purbeck mammals remains no stronger than I have re- 
corded, then the weight of evidence is against the suggested 
mammalian interpretation ; but the resemblance in the form 
of the crown in these two types of teeth is sufficient to make 
further evidence desirable of the root character in those mam- 
mals, before the tooth which has hitherto passed unchallenged 
as Nuthetes is accepted unreservedly ‘as a reptile-tooth which 
has abnormally developed a divided root. 
