128 
FOSSIL JAWS OF MACROPODID^J, 
portion o£ the true molars. Molars smooth. Lower premolar 
tricuspid. Palate entire. Size large. 
Dimensions. 
Maxillary. — Length of the cheek-teeth 70*5 (estimated), of the 
first four 55-5 (1); of p. 4 11-0 (1). Width of m. 3 12-5 and 12-8 
(2). 
Mandibular. — Length of the cheek-teeth 57*0 to 62'6 (2); of 
p. 4 7-0, 7-2 and 8-0 (3); of p. 4 , m 1 18-0 (1). Width of m. 3 9-5 
to 10-1 (2); anterior depth 25-8 and 29'0 (3); posterior 28-0 and 
29-0 (2). Thickness 19'7 and 21 -0 (2). Internal length 82-0. 
Form. 
Maxillary. — P. 4 (PI. xvin. fig. 4) irregularly elongate-ovate, 
tricuspid; the mesial cusp the shortest, cuneiform; the anterior 
a compressed cone. The large inner portion of the posterior cusp 
is fused with the outer; its posterior base folds backwards and 
outwards behind the base of the outer portion so that the posterior- 
surface of the tooth has a remarkable resemblance to that of the 
molars of the kangaroos. The inner ledge is represented by a 
low basal tubercle opposite the interval between the anterior and 
mesial cusp. Diameters 11*0 and 4*6. 
Molars (PL xvin. fig. 5) not distinguishable in form from those 
of M. magister and pan. 
Mandibular. — P 4 (PI. xvin. fig. 3). Diameters 8*0 and 3*4. 
Tricuspid, elongate-ovate. Crest parallel with outer side, curving 
inwards posteriorly; mesial cusp the shortest, cuneiform. Crown 
tumid on intero-posterior angle but not developing a distinct cusp. 
Molars (PI. xvin. fig. 6) as in M. magister and pan. 
Lower contour line of mandible undulatory. 
Rise and fall of teeth. 
The mandibular premolar is j)rocumbent on the verge of the 
diastema when the hind lobe of m. 4 is just showing effects of 
wear. 
