146 PEOCEEDINGS OP THE GEOLOGICAL SOCIETY. [Jan. 13, 



surface of the bone, while of the inner series the four hindmost 

 teeth are but little affected by wear. The teeth of the outer series 

 are larger than those of the inner, the base of the largest being 

 0-15 in. in diameter ; the middle teeth in each series are the largest, 

 the anterior and posterior diminishing in size. 



The inner two series of teeth cannot be traced as far forward as 

 the outer, the inner wall of the anterior half-inch of this valley 

 being so thoroughly ground down that it is converted nearly into a 

 plain. It is a curious circumstance that at the posterior part of the 

 inner surface the apices of four teeth appear, as if they were about 

 to protrude on this face. It is quite clear that this remarkable 

 wearing down of the palato-maxillary teeth can only be explained 

 by their attrition against the teeth of the mandible ; and the sharp- 

 ness of the groove in the posterior half of the palatal surface clearly 

 shows that these mandibular teeth were themselves sharpened to a 

 sort of knife-edge. 



Dr. Lloyd's second specimen is a fragment of a larger palato- 

 maxillary bone of the same (left) side. It is, however, smaller 

 relatively to the original size of the bone, as some of the anterior 

 portion is broken away, and the posterior edge, though nearly pre- 

 served, is somewhat imperfect. The transverse diameter of the 

 nearly entire posterior end is 0*8 in. ; so that this bone is about half 

 as large again as the foregoing, and belonged to an animal probably 

 not more than half as large as the Elgin specimen. 



In this specimen the outer series of teeth is double posteriorly, 

 two large conical teeth making their appearance on the outer side 

 of the four which remain tolerably unworn. As before, there are 

 two rows on the inner side of the groove ; and anteriorly all the 

 series of teeth are worn down to one flat surface with the bone 

 which holds them. 



Mr. Whitaker's specimen *, from Devonshire, is a right palato- 

 maxillary bone of a Hyperodapedon of small size, probably less than 

 that to which Dr. Lloyd's smaller specimen belonged. It is in an 

 imperfect condition, bat shows part of a single outer series of teeth, 

 and of two inner series, both completely worn down. The apices of 

 four or five teeth project in two rows upon the posterior half of the 

 inner face of this specimen. 



I propose to give a full account of the Indian specimens elsewhere. 

 At present I merely wish to observe that, for the most part, they 

 belong to animals of a larger size than the Elgin specimen, but that 

 I have not yet discovered any grounds for regarding them as specifi- 

 cally distinct. In the series sent by Dr. Oldham, there is a frag- 

 ment of a ramus of a mandible which shows the scissor-edge cha- 

 racter of the dentary margin extremely well. 



* I am indebted to my friends the Rev. P. !B. Brodie and Mr. Kershaw for 

 drawing my attention to some additional examples of the Warwickshire Hy- 

 perodajpedon. Two of them are fragmentary palato-maxillary bones. The third 

 has very much the appearance of two crushed palato-maxillary bones, with one 

 ramus of the mandible of a small specimen ; but I have not been able to work 

 it out fully. 



