406 



is not another outlet of the suborbital canal, but leads obliquely downward into the 

 entrance or substance of the maxillary bone. Of this foramen (a) I have not seen a trace 

 in any existing Kangaroo, save Macropus crubescens (Plate LXXX. fig. 1, a). The degree 

 of attrition of the upper molars in fig. 11, Plate LXXXII., agrees with that of the lower 

 molars in fig. 14, ib. The exposed tract of dentine in d i is continuous, the mid link being 

 worn down to its base ; the fore part of the crown is broken off. In m i the front lobe 

 is worn down to the level of the prebasal ridge, which is well marked, overlies the back 

 part of d 4, and shows a rudiment of a link or mid rising to the front lobe of its own 

 tooth. The line of abrasion of this lobe is from without inward and a little back- 

 ward, not transverse to the skull's axis : a mid link is continued from it to the middle 

 of the front surface of the hind lobe ; this is worn, but not so as to obliterate the 

 oblique outer cleft dividing it from the postbasal ridge which rises to be lost in the 

 inner end of the hind lobe. 



In m 2 the characteristic configuration of the crown of the upper molar of Macropus 

 Titan is well shown. The two chief lobes are more nearly transverse in the direction 

 of their summits than in Macropus major ; the prebasal ridge with its linking process 

 and the mid link are as well marked as in that species, and the oblique postbasal ridge 

 is longer. In the last upper molar of Macropus Titan this ridge (g), which is almost 

 obsolete in Macropus major, is as well marked as in the preceding molar, m 2. The 

 mid link of the last molar is more curved than that of m 2 ; the concavity of the curve 

 is turned inward. 



Compared with the molars of Sthenurus Atlas (Plate LXXXIV. fig. 6) the prebasal 

 ridge is rather more developed, the mid link is thicker, the outer and inner sides of the 

 transverse ridges are thicker and more prominent, and the fore-and-aft extent of the crown 

 is relatively greater. 



The crowns of the upper molars are, as usual, broader than those of the lower jaw, 

 and, as in Macropus major and Nototherium, the last lower molar has a greater longi- 

 tudinal extent of grinding-surface than the tooth above. 



In another specimen of a smaller portion of the left maxillary of Macropus Titan in 

 the University Museum of Geology, Oxford, the dentition is shown at the same phase 

 of development as in the preceding fossil, with a rather greater degree of abrasion. A 

 thin line of dentine is exposed upon the summit of the anterior lobe of ?n 3 ; the mid 

 link is worn to its base, exposing a linear tract of dentine uniting the broader field upon 

 the anterior and posterior lobes. The size and other characters of the upper molars in 

 tigs. 10-14 (Plate LXXXII.) are satisfactorily repeated in the present evidence of 

 Marropus Titan. 



Both specimens are from the freshwater beds or drifts of Queensland, and were pre- 

 sented to the Oxford Museum by Sir Charles Nicholson, Bart., M.D., and formerly 

 Speaker of the Legislative Assembly at Sydney, New South Wales. 



The portion of right upper maxillary (Plate LXXXIII. figs. 2 & 3) in which the adult 

 series of five gr inders had been acquired, but with posthumous mutilation of the crowns 



