BY C. W. DE VIS. 123 



last three molars from 41-5 to 45*0 (3); of the last two from 31-2 

 to 34-1 (7); m.^ is 15-5 and 16-9 (2); the premolar from 9*0 to 

 10-5 (5); the first four cheek-teeth from 43*7 to 46*7 (2); the first 

 three molars from 40-0 to 45.0 (3); m-, m."^ from 30-1 to 32-0 (6); 

 m.-5 from 15-6 to 17-6 (6); m.- 12-6 (bis.). 



Young: P.'^, mp.*, m.^, m.-, m.^ are 56*7 and 63-5 (2); p.^, 

 mp.*, m.i, m - 45-2 and 45-4 (2); p. 3, mp.'^, m.^ are 35-5 (1); 

 p.^ mp.-^ 20-4 (1); p.-^ from 9-0 to lO'O (6); mp.^ m.^, m.^ from 

 35-4 to 38-7 (3); mp.\ m.^ 26-5 (1); m.i, m.- 25-8 and 27-7 (2); 

 m.3 from 14-2 to 16-4 (3). 



The widths of the lower and uj)per teeth are as 13 to 14; in 

 M. yiganteus the ratio is 7:8; in M. robustus 19:20; in most 

 other recent species the difference is much greater than in M. 

 giya^iteus. 



Tn mandibular dimensions M. inayister has no special relation 

 to either of the recent kangaroos. Though the length of its 

 cheek-teeth is but little more than a fourth greater, the mean 

 width of the series at m. ^ is more than twice as great, while the 

 thickness of the mandible and its depth are only about one-half 

 greater than in M. giganteus, rohustus and rujus. In range of 

 depth it somewhat exceeds the greatest attained by a recent 

 species, H. dorsalis, to wit. 



Form. 



Mandibular. — P.* (PL xviii. fig. 12) is short, with mesial diame- 

 ters 7-0 : 3-5. Anterior lobe the shorter, longitudinall}^ com- 

 pressed, lancet-shaped; the posterior single, or with its anterior 

 two-fifths forming a subdivision obscurely defined by a vertical 

 groove on the outer side, and a notch in the crest. Crest curving 

 without interruption on to the intero-posterior cusp, which is only 

 separated from the lobe by a shallow vertical groove on the upper 

 mesial part of the posterior surface, and forms with it anteriorly 

 a concave intero-posterior face. 



P. 3 (PI. XVIII. fig. 11) is short, with mesial diameters 8*9 : 4-5, 

 similar to p.* in structure, but larger in size. The anterior lobe 

 is relatively larger; the intero-posterior cusp is higher than the 



