212 DR. EMBLETON AND MR. ATTHEY ON THE 



side. From this specimen, and from another in Mr. Atthey's 

 possession, it can be discerned that the articular surface was a 

 rather deep, transversely elongated, and smooth groove, rather 

 more elevated in the middle than at the ends, for the reception 

 of the condyle of the upper jaw, which was similarly elongated, 

 and whose ends were gently raised above the level of the middle. 



In another specimen in Mr. Atthey's collection, larger than 

 the subject of this paper, the length of the articular groove on 

 the mandible is one inch and three-quarters, the breadth half 

 an inch, and the greatest depth a quarter of an inch. The pos- 

 terior border of the articular surface curves upwards and for- 

 wards, so that the joint, though it was not interlocked, must 

 have been pretty secure. The articular part of the jaw projects 

 outwards from the plane of the ramus half an inch. The inner 

 surface is not visible in this, but can be well seen in the other 

 half -mandible. 



It will be observed that the teeth in the right half are all 

 entire, whilst those of both sides of the maxilla and, as will be 

 seen in the sequel, those in the left half-mandible are all broken 

 off short. The difference is thus accounted for : in the matrix 

 they were all entire ; but on this being broken up, the teeth, 

 being firmly anchylosed to their sockets, could not come out ; 

 but the parts above the alveoli, being firmly imbedded and en- 

 tangled in the matrix, have been broken away with it and lost ; 

 moreover the weakest part of the teeth is immediately above the 

 alveolar border. In the case of the right half-mandible, which 

 was obtained with the shale around it, this matrix has been 

 carefully worked and cautiously chipped away, leaving the teeth 

 in situ, exposed on their outer surface, but left supported by the 

 shale on the other side. 



There are upwards of twenty teeth in this half -jaw : seventeen 

 or eighteen are well preserved; a dozen are entire. They vary 

 much in size, and are irregularly arranged, in some parts being 

 nearly in contact with each other, in others considerably apart. 

 Three are much larger than the rest, and seem to correspond to 

 the vomerine and palatal tusks of the upper jaw. These large 

 teeth are one inch and a half long, and upwards of half an inch 



