62 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 20, 



two outer cones. The posterior one, c, is connected by a ridge, which 

 advances inward and forward, to the interspace between the anterior 

 pair of cones. 



The first molar, m 1, with an increase of size over the last pre- 

 molar, also shows an equal development of both fore and hind pair 

 of lobes ; the summits of the two outer lobes are more abraded than 

 those of the two inner ones, and the dentine is exposed in each. 

 The same oblique ridge is continued from the fore part of the postero- 

 external lobe to the interspace between the anterior pair : the cin- 

 gulum is not developed upon the internal part of the tooth, but it is 

 upon the external part, and especially upon the anterior lobe : pos- 

 teriorly it forms a kind of low talon wedged into the interspace of the 

 hinder pair of lobes. 



The second molar, m 2, shows an increase of size ; but its chief 

 and most interesting modification is the development of a tubercle, e, 

 between the two anterior lobes, making three cones on the same 

 transverse line, and thus repeating the character of the molar tooth 

 above. The oblique ridge from the outer and hinder lobe, c, abuts 

 against the intermediate anterior tubercle, e. The inner surface or 

 plane of the inner and hinder cone, d, inclines as it extends forward 

 toward the middle of the crown : the fore parts or prolongations of 

 the hinder cones thus converge as they pass forward toward the 

 middle of the crown. The cingulum extends from the back part of 

 the crown along the outer side to the fore part. Both this and the 

 preceding molar are implanted by four roots. 



The third molar, m 3, is distinguished by its greater fore-and-aft 

 extent, due to its additional or third lobe. The ordinary two pairs 

 of cones resemble those of the preceding molar, but the intermediate 

 tubercle between the anterior pair is reduced to a short connecting 

 bar. The hind lobe appears to have been divided into two small 

 cones, but this part of the tooth was fractured in the attempt to 

 remove the very hard and adherent matrix. 



I beg to express my obligations to the accomplished artist, Mr c 

 Ford, for the pains which he has bestowed in attaining the utmost 

 accuracy in the figures above referred to. 



Affinities of the Pliolophus vulpiceps as shown by the skull and 

 teeth. — Before proceeding with the description of the other parts of 

 the little quadruped which have been extricated from the septarian 

 nodule, it may be convenient to record here the deductions as to the 

 nature and affinity of the Pliolophus vulpiceps which may be drawn 

 from the skull and teeth. 



The form of the articular surface for the lower jaw, and above all 

 that of the mandible itself, demonstrate the ungulate and more or 

 less herbivorous nature of Pliolophus. Amongst recent non-rumi- 

 nant Ungulates, Tapirus offers the nearest resemblance in the dispo- 

 sition and form of the zygomatic arch, and in the general form of 

 the lower jaw : amongst the extinct Ungulates, Palceotherium most 

 resembles Pliolophus in the same parts of the skull, with a nearer 

 approach than the Tapir makes, in the production of the nasal 



