102 
FOSSIL JAWS OF MACROPODID^E, 
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. — (PL 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 
within 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 
9 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 teeth. 
No precise information as to the relative periods of change of 
teeth can be gathered from the examples at present available for 
study. 
Exan ip les — seven 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. 3 and three 
following teeth — Eight without the deciduous premolar. 
Maxillary. — Three maxillse with all the cheek-teeth — One with 
all the true molars — Five with sundry teeth and a young maxilla 
with mp. 4 , m. 1 , m. 2 . Of fourteen supplemental — 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. 
