274 Prof. H. G. Seeley on a 



XLVIII. — Supplemental Note on a Double-rooted Tooth from 

 the Purheck Beds in the British Museum. By H. G. Seeley, 

 F.R.S. 



In describing this specimen no reference was made to the 

 possible resemblance of the tooth to the canine teeth of 

 Mammals. The division of the root, and the absence from 

 the margins of the crown of the serrations, seen in well- 

 preserved, teeth o^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.S., 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. I have gone over the 

 evidence with Mr. Smith Woodward, and give the results. 



First, examples of the teeth of Nuthetes occur which iiave 

 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 witii 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 those teeth show no trace of serrations 

 upon their lateral margins. Secondly, Professor Marsh 

 (Amer. Journ. Sci., April 1887, vol. xxxiii. pis. 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 Dryolestida3 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- 



