470 



developed on the inner side of the hind link (ib. s), where it is divided from the hind 

 lobe by a fossa ; on the outer side of the link the ridge ((f) rapidly sinks and subsides 

 near the base of the crown ; the mid part of the postbasal ridge is half an inch above 

 the base-line of the enamel in m \ (fig. 8). The main valley expands as it descends from 

 each side of the mid link (r), and is closed by a low bar on both the outer (ib. fig. 6, v) 

 and inner (ib. fig. 5, v') sides of the tooth. The fore-and-aft extent of m i is 1 inch ; the 

 transverse diameter of the hind lobe is 8 lines. 



The less worn crown of m 2 shows better the pattern of the grinding-surface in the 

 lower molars of the present species. The vertical indent (ib. fig. 1, hu) on the inner 

 and fore part of the crown, leading to the better developed inner part of the prebasal 

 ridge (ib./), is deeper than in m 1, and causes a concave contour of the anterior enamel- 

 border of the fore lobe. The mid link projects from the middle of the hind enamel- 

 border of that lobe, touches, but is not continuous with, the hind part of the link (r) 

 sent off from the outer side of the fore part of the hind lobe (b). The vertical promi- 

 nence from the corresponding part of the crown of the lower molars in Nototherium 

 (Plate XLIV. figs. 2 & 3, r) is the homologue of this part of the mid link in Palorchestes. 



The inner concave part of the fore surface of the hind lobe shows two fine vertical 

 fissures in m 2 (fig. 2). From the low link at the back of the hind lobe the postbasal 

 ridge sinks toward the base, thicker and shorter on the inner (fig. 2, m 2, g) than on the 

 outer side. The fore-and-aft extent of m 2 is 1 inch 1^ line (29 millims.) ; the transverse 

 breadth of the hind lobe is 8^ lines (18 millims.). 



That of the fore lobe of m 3 is 9 lines ; the length of the crown, if entire, would be 

 1 inch 2 lines (fig. 4). The fracture at which the hind lobe of that tooth has been 

 broken away shows the continuous part of the mid link to be 3 lines in vertical extent ; 

 the whole height of the link being 5 lines where it rises from the valley (ib. fig. 3, m 3). 

 The exposed hind root of this molar curves outward as it descends, and is bifurcate at 

 the extremity. Beneath it the fracture shows the dental canal. The inner bar is hardly 

 marked at the inner entry of the valley in m 2 and m » (fig. 4). The enamel near the 

 base of the crown and at parts of the outer surface shows the fine rugae and punctations 

 like those in the molars of Nototherium and Diprotodou. One cannot help seeing in the 

 generic pattern of the molars of Palorchestes a transitional condition between the small 

 existing Kangaroos and those extinct gigantic Marsupials. 



A restoration of the skull of Palorchestes Azael is added, in outline, to a view of the 

 left side of the subject of Plates XCVI. & XCVII. in Plate CVII. 



