G4 Mr. Owen on the Phascolotherium. 



evidently separated by wider intervals than in Thylacinus, Dasyurus or Didelphys ; 

 and the Phascolothere resembles, in this respect, as in the smaller proportions of 

 its canine, the genus Myrmecobius. 



In the proportions of the grinders to each other, especially the small size of the 

 hindmost molar, the Phascolothere resembles the Myrmecobius more than it does 

 the Opossum, the Dasyure or the Thylacine ; but in the form of the crown it resem- 

 bles the Thylacine more closely than any other genus of Marsupials. In the num- 

 ber of molar teeth the Phascolothere differs both from the Thylacothere and the 

 Myrmecobius, and resembles the Opossum and Thylacine, having three false and 

 four true molars, or seven grinders altogether, in each maxillary ramus. The di- 

 stinction betweenthe 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 addi- 

 tion, 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 Phascolothere, 

 as in the Thylacine, there is no corresponding tubercle on the inner 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 quinquecuspid appearance to the crown of the tooth, as repre- 

 sented by Dr. Buckland in his magnified view of the antepenultimate 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 characteristic 

 features of the ascending ramus of the jaw, I am of opinion that the marsupial ex- 

 tinct genus, indicated by the Stonesfield fossil here described, was nearly allied to 

 Thylacinus, and that its position in the marsupial series is between Tliylacinus and 

 Didelphysi 



There are two linear impressions on the inner side of the horizontal ramus of 

 the jaw of the Phascolothere which have been mistaken for indications of harmonia, 

 or toothless sutures, analogous to those which join together the component pieces 

 of the compound jaws of reptiles and fishes. One of these is a faint, shallow, 

 linear impression, continued from between the antepenultimate and penultimate 

 molars, obliquely downwards and backwards, to the foramen for the dental artery. 

 I conceive it to be due to an accidental crack ; and if the portions of the bone 



