274 
PEOFESSOE OWEN ON THE EOSSIL MAMMALS OF AUSTEALIA. 
The extent of the alveolar part of the maxillary in advance of the masseteric process 
is relatively greater than in Macropus major , and more resembles that in the Kangaroos, 
which longer retain the premolar and which have that tooth of larger relative dimen- 
sions than in the type of Macropus proper. The amount of fracture and variety of 
distortion which this cave cranial fragment has undergone indicates a persevering exercise 
and diverse direction of force, such as only accords with the operations of the powerful 
jaws of a large carnivore. 
§ 9. Genus Protemnodon *, Ow. — The genus Protemnodon is allied to Sthenurus, but 
distinguished therefrom chiefly by the more simple trenchant shape of the crown of the 
premolar. 
Having ascertained the characters of that tooth in the upper jaw of Sthenurus Atlas , 
in the specimen from the lacustrine deposits of South Australia (Plate XXIV. figs. 4, 5, 6), 
I subjected to a reexamination the fossil upper jaw brought to me in 1842 by Count 
Strzelecki from the Breccia-cave of Wellington Valley, and the specimen transmitted in 
the following year from the bed of the Condamine by Col. Sir Thomas L. Mitchell, 
C.B., both of which specimens, from the size of the germ of the premolar (Plate XXIII. 
figs. 6 & 9), had been referred, in my £ Catalogue of the Fossil Mammalia in the Royal 
College of Surgeons,’ to Macropus At las f . 
I had fortunately begun the quest of this tooth from the inner side of the formative 
alveolus, and was now able to recognize, in the absence of the inner ridge or lobe 
characteristic of the upper premolar of Sthenurus , and giving the crown of that tooth a 
breadth corresponding with the lower premolar, that the fossils Nos. 1513, 1519 must 
belong to another species, and, according to the estimate of the value of premolar 
modifications, to another subgenus of Macropodidce. 
The subsequent acquisition of mandibular fossils, with the premolar simple and 
trenchant, and with equivalent modifications of the form of the bone, have afforded the 
requisite ground for proposing the genus, and for referring these maxillary specimens to 
the species Macropus Anak , originally founded on characters of the lower jaw and teeth. 
The upper molars of Protemnodon are more like those of Sthenurus Atlas than of 
Macropus Titan ; they have a narrow prebasal ridge without the link. The oblique 
ridge extending downward and backward from the inner and hinder angle of each chief 
lobe is more definitely marked, and the two lobes are more alike than in Sthenurus 
Atlas. The breadth of the crown in m i and m 2 of Protemnodon Anak (Plate XXIII. 
figs. 5 & 8) is greater in proportion to the fore-and-aft length than in Sthenurus; and 
the inner border of the two lobes (ib. figs. 6 & 9) is narrower and more sharply pointed 
than the outer border (ib. figs. 4 & 7), in a more marked degree even than in Sthenurus. 
Proceeding to the characters afforded by the mandible and teeth (Plates XXV. & 
XXVI.), I have first to remark that the premolar (p 3 in all the figures), in its relative 
antero-posterior extent to the molars which follow, rather exceeds that tooth in Sthenurus 
*' wpo (before), re/irw (to cut), ooovs (tooth) — in reference to the sectorial form of the anterior molar or premolar. 
t 4 to, 1845, pp. 325, 327, Nos. 1513, 1519. 
