Page:Quarterly Journal of the Geological Society of London, vol. 26.djvu/643

1870.] BUSK RHINOCEROS OF ORESTON. 461 Rhinoceros that tooth is usually much more rectangular than m 2. Moreover, on comparison, these teeth will, I think, be found to agree more closely with the m 2, of which a figure is given by Mr. W. Boyd Dawkins in his paper on the dentition of R. leptorhinus

Fig. 2. — Right Upper Molar of Rhinoceros from Oreston.

i. Remains of posterior sinus. (Other letters the same as in Fig. 1.)

(R. megarhinus, B. D.) in the ' Natural History Review ' (vol. v. p. 409), than with the m 1 there represented. The point, however, is not one of any great importance.

Both the teeth, as before remarked, are much worn — the remaining height of the crown from the root of the fangs, measured on the dorsum, being about 2 inches. In the specimen, no. 878 (Fig. 1), which is of the left side, the anterior column is entire, and the remains of the very oblique and strongly developed anterior vallum or " guard," a, can be seen on its anterior face only, not encroaching at all upon the internal face. The entrance of the median sinus (" anterior valley "), b, presents two rather strong conical papillae or cusps, whose points are slightly worn. The hinder part of the tooth, including the greater portion of the posterior column, is broken off. The uncus (" crochet "), c, is long, tapering, and curved outwards, so that its point is directed towards the anterior outer angle of the tooth. So far as it is worn down, and for a short distance beyond the worn surface, the uncus is free ; but at a greater depth it is joined to the anterior column by a narrow isthmus, so