274 Prof. H. G. Seeley on a 
XLVIII.— Supplemental Note on a Double-rooted Tooth from 
the Purbeck Beds in the British Museum. By H.G.SEELEY, 
F.R.S. 
In describing this specimen no reference was made to the 
ossible resemblance of the tooth to the canine teeth of 
fammals. The division of the root, and the absence from 
the margins of the crown of the serrations, seen in well- 
preserved teeth of Nuthetes, not unnaturally raised the question 
whether the tooth may not be mammalian; in which case its 
interest would be increased, since no example of such a 
structure has been figured, though it is affirmed to exist in 
the Jurassic Mammals of this country and America. Such 
doubts have already arisen; and Mr. Arthur Smith Wood- 
ward, F'.L.8., has mentioned to me his belief that the tooth 
is a mammalian canine, and ought therefore to be removed 
from the series of teeth of Nuthetes. J have gone over the 
evidence with Mr. Smith Woodward, and give the results. 
First, examples of the teeth of Nuthetes occur which have 
lost the serrations of the crown. Secondly, a tooth of 
Nuthetes, of which only a small portion of the crown is pre- 
served, shows an impression which is so like a divided root, 
that it closely approximates the condition of the fossil which 
I figured. Other teeth of Nuthetes have the root vertically 
furrowed, and it sometimes happens that there is a distinct 
pit of some size at the base of the crown; so that with close 
correspondence of the shape of the crown of the figured tooth 
in question to certain undoubted teeth of Nuthetes, the modi- 
fication is not a remarkable one which would give a divided 
root as an abnormal condition ; and though the evidence is 
small in amount, it arrests attention. 
On the other hand, the crown of the tooth has some re- 
semblance to the crown of a canine of one of the small 
mammals from the Purbeck beds; and the comparison has 
this advantage that thosé teeth show no trace of serrations 
upon their lateral margins. Secondly, Professor Marsh 
(Amer. Journ. Sci., April 1887, vol. xxxiii. pls. 9 & 10) has 
affirmed the divided condition of the roots of the canines in 
the allied American genera, as a common character. It is 
difficult, in the absence of specimens, to determine what im- 
portance to attach to these observations, since no example of 
a divided root, so far as I remember, has been figured. It is 
stated that in the Dryolestide the canine is inserted by two 
roots more or less distinct. Laodon in this family is men- 
tioned as having two roots to the canine. In the Diplo- 
