441 



near the cutting edge, shows the shallow indent caused by the crown of the second 

 incisor ; but this tooth, in both premaxillaries, has been displaced by the lateral crushing 

 of these bones in the recent state, and was probably lost prior to the imbedding of the 

 skull. The second incisor is the smallest and least deeply implanted in most Kangaroos. 



The third incisor (ib. ib. i 3 ) had not been fully developed ; its crown has only partially 

 emerged from the socket, whence its preservation. It is in the form of a scalene triangle ; 

 the shortest side is turned forward, the longest forms the cutting edge, which is notched 

 anteriorly by an oblique groove extending from near the middle of the outside of the 

 crown down to the cutting edge, then inward and forward along that edge to near the 

 antero-inferior angle of the crown. The grooved part of the edge in its present unworn 

 condition thus presents two trenchant borders. The fore side or border of the crown 

 shows an anterior low convex ridge through the subsidence of the enamel between this 

 and the mid groove ; the enamel behind this groove is again at a lower level ; thus the 

 antero-posterior lay of the outer enamel is undulated. The fore-and-aft extent of the 

 exposed crown is 6 lines ; the front border or side of the triangle measures 5 lines. 



The indent caused by the second incisor is present on both right and left anterior 

 incisors ; the interspace between the first and third incisors from which the second has 

 been pushed is greater on the left than on the right premaxillary. A detached fully 

 developed third incisor of a full-grown Sthcnurus Atlas is figured in Plate LXXVII. 

 fig. 5. 



In the lower jaw of this species (Plate LXXXII. fig. 5) the interval between the 

 molars and procumbent incisor is less than in Macropus Titan (ib. fig. 13). The present 

 specimen shows that a similar character marks the upper jaw. The extent of the 

 maxillo-premaxillary diastema is, here, 10 lines, but would be, of course, greater in the 

 full-grown Kangaroo. 



The anterior molar (Plate LXXVI. fig. 2, d 2) with a crown 6 lines in antero-posterior 

 extent, shows a depressed middle tract of the outer surface traversed by two vertical 

 ridges. The inner surface, which forms posteriorly a prominent convex lobe, sinks 

 rapidly to a basal ridge as it extends forward to a low angle on the inner side of the 

 anterior division of the tooth. The second molar (d 3) has a prebasal ridge without the 

 fore link ; the mid link is small and low placed, in chief continuation with the inner 

 angle of the fore lobe. The hind surface of the hind lobe has a triangular excavation. 



These characters are repeated in d 4 and m 1 ; the crown of the latter is protruding from 

 the formative cell, and is unworn. The crown of the premolar, exposed in its formative 

 cavity, is incomplete with the concomitant wide and deep excavation at the basal part 

 for the unexhausted pulp. The longitudinal grooves and ridges of the trenchant apical 

 border, part of which are visible in the worn premolar of the subject of fig. 4, Plate 

 LXXXIV., are well shown in the germ of the premolar in that of fig. 4, Plate LXXVII. ; 

 its fore-and-aft extent agrees with that of the fully developed homologue, viz. 9 lines 

 = 18 millims. 



The bony palate, so far as it is preserved, appears to have been entire. 



