Tertiary.] PALZONTOLOGY OF VICTORIA. [ Mammalia. 
same point, 1 inch 1 line; lower edge of jaws gbtuse, slightly inflected at angle, 
external side convex, internal face flatter. In this jaw the transverse ridges of the 
last molar in place m? are scarcely worn, and the links not at all; the other molars 
are successively more and more worn to the front. The front molar d” has the 
grinding surface obliquely triangular, the obtusely rounded apex in front; the outer 
side divided a little in front of the middle by a deep vertical sulcus separating two 
convex lobes; the inner side flatter, with three short, subequal, nearly vertical, shallow 
grooves on the middle third, crenulating the crown, but only extending a short way 
towards the base; three small oblique tracts of dentine exposed by wear of the 
enamel. The second molar d* has a distinct prebasal ridge, two transversely 
oblong spaces of dentine exposed by the wearing of the front and back lobes, but 
the mid-link scarcely divided by. a sliht line “of dentine. The third molar dé 
with the dentine exposed by wearing of the whole transverse length of the ridge of 
the anterior lobe, but only at the outer extremity of that of the hinder lobe; the 
links and prebasal ridge unworn. Fourth and fifth molars m1 and m? unworn, 
(Adult.)—Lower jaw “with one premolar p*? and one deciduous molar d*, and 
three true molars in place, affords the following measurements :—Length of entire 
molar series from anterior edge of premolar p® to hind edge of last molar m°, 
3 inches 8 lines: antero-posterior length of premolar p*, 7 lines; greatest width 
of hind-lobe, 5 lines; of anterior lobe, 3% lines: length of deciduous molar d+, 7 
lines; width, 64 lines; leneth of first true molar m1, 83 lines ; width of front-lobe 
7 lines ; width of hind. lobe, 64 lines: length of second ‘molar m’, 84 lines; width 
of anterior lobe, 73 lines; ‘of posterior lobe, 63 lines: length of last molar m®, 10 
lines; width of anterior lobe, 7 lines; of posterior lobe, 64 lines. The dentine 
exposed on the transverse ridges of all the teeth. 
REFERENCE.—Macropus Goliah (Owen), in Waterhouse, Nat. Hist. Mamm.., pt. 
2, p.59; Phil. Trans. Lond., vol. 164, p. 791. 
In the shortness and depth of the symphysial part of the jaw, 
the thickness of the premolar especially behind, and in the thick- 
ness and depth of the rami, and their firm union in front, and in the 
upward inclination of the incisor teeth, the Procoptodons approach 
more to the Nototherium than any of the other Macropodal genera 
do. The animal was probably more robust, and with thicker, and 
shorter, and more equal legs than living kangaroos. 
This, the most gigantic species of the extinct genus Procopto- 
don, is not uncommon in the Pliocene deposits of Victoria, generally 
in company with the much commoner Macropus Titan. The 
specimens figured are from the Pliocene Tertiary clays of Lake 
Timboon, on the shores of which they are cast up after storms, 
with various extinct species of Macropus, the Phascolomys pliocenus 
(McCoy), and the Zhylacoleo carnifex (Owen), &c. 
EXPLANATION OF FIGURES. 
: 
Plate LII.—Fig. 1, side view of exterior side of ramus of lower jaw or mandible, natural size, 
showing the socket of incisor of same side and inner view of incisor of the opposite side, adhering 
by the strong bony anchylosis of the jaws in front (contrasting with the loose jaws of Macropus) ; 
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