102 FOSSIL JAWS OF MACROPODIDAi, 



posteriorly, where it makes an open curve to the apex of a large 

 intero-posterior cusp; outer surface of crown with a short im- 

 pression faintly marking the limit of an anterior cusp; inner 

 surface concave longitudinally, with two or three moderately 

 strong ribs; in one example a deep depression between the 

 extero-posterior angle of the lobe and its crest demarcating a sort 

 of basal talon. Diameters 8-4 : 4-0. 



Molars. — (PI. xvi. fig. 15). At the point in which each obliquely 

 descending revolute edge of a lobe becomes a longitudinal link 

 there are one or two more or less compressed processes rising 

 wdthin the inner side of the link; these either ascend upon the 

 face of the lobe or stand out from it, and sometimes by confluence 

 and extension upward and inward simulate on that side the 

 oblique edge of the other side. These or traces of them are 

 constant whenever the tooth is not too far gone in wear. The 

 posterior talonal protuberance is also constant and occasionally 

 rises obliquely on to the base of the inner side of the tooth. 



Rise and fall of teetJi. 



No precise information as to the relative periods of change of 



teeth can be gathered from the examples at present available for 



study. 



Examj) les — sevei i. ty-six. 



Mandibular. — Of adults: Five rami with the full series of 

 cheek-teeth — ^Thirty-five rami or portions thereof with teeth in 

 greater or less number. Of young : Four rami with p. '' and three 

 following teeth — Eight without the deciduous premolar. 



Maxillary. — Three maxillae with all the cheek-teeth — One with 

 all the true molars — Five with sundry teeth and a young maxilla 

 with mp."^, m.i, m.-. Of fourteen supplementary — all are clearly 

 identifiable by the characters peculiar to the species. 



Halmaturus thor, n.s. 



Molars with crests subrectilinear, lobes moderately thick, 

 angles rather rounded and links feeble. 



