PHASCOLOTHERIUM. 67 
and the AMyrmecobius, and resembles the Opossum and 
Thylacine, having three false and four true molars, or 
seven grinders altogether, in each maxillary ramus. The 
distinction between the false and true molars is however 
much less strongly marked, both in the Phascolothere 
and Thylacine, than in the Opossum. The difference be- 
tween the false and true molars in the Opossum is chiefly 
indicated by the addition, in the true molars, of a pointed 
tubercle on the inner side of the middle large tubercle, and 
in the same transverse line with it; but in the Phascolo- 
there, as in the Thylacine, there is no corresponding tuber- 
cle on the imner side of the large, middle, pointed cusp ; 
its place is occupied in the Phascolotherium by a ridge, 
which extends along the inner side of the base of the crown 
of the true molars, and, projecting a little beyond both the 
anterior and posterior smaller cusps, gives the quinquecus- 
pid appearance to the crown of the tooth, as represented 
by Dr. Buckland in his magnified view of the antepenulti- 
mate grinder of the Phascolotherium, given in the 2nd 
Plate of the illustrations of the Bridgewater Treatise. In 
the Thylacine the internal ridge is not continued across the 
base of the large middle cusp, but it extends along and 
beyond each of the lateral cusps, so as to give the tooth a 
similar quinquecuspid form to that which characterizes the 
true molars of the Phascolothere. Connecting the close 
resemblance which the molar teeth of the Phascolothere 
bear to those of the Thylacine with the similarities which 
have been already shown to exist in the several character- 
istic features of the ascending ramus of the jaw, I am of 
opinion that the marsupial extinct genus, indicated by the 
Stonesfield fossil here described, was nearly allied to 
Thylacinus, and that its position in the marsupial series is 
between Thylacinus and Didelphys. 
