BY C. W. DE VIS. 85 



Dimensions. 



Mandibular. — The length of the entire series of cheek-teeth is 

 94-7 (1); of the series of true molars 80-0 (1); of the last three 

 molars 58-3 (1); of the last two 39-4 and 41-6 (2); of the last 

 22-0 and 22-1 (2); of m.-, m/^ 37-0 (1); of m.-^ 22-1 (1); of m.^ 

 20-2 (1); of the premolar 15-0 (1); of mp.-^ 18-5 (1). The width 

 of m.^ is from 12-3 to 14-2 (7). The anterior depth is 40*6 and 

 48-3 (2); the posterior from 35*4 to 49-0 (10); the thickness from 

 21-8 to 29-9 (10). 



Maxillary. — The length of the first four cheek-teeth is 55-9 (1); 

 of the first two molars 37-6 (2); of the last two 37 9 (1); of m.^ 

 21-2 and 21-5 (2); of m.^ 19-7 (1); of m.- 20-5 and 2M (2). 

 The width of m."^ is from 15-8 to 16-6 (3). The length of the 

 premolar is lo'O (1). 



The mean widths of m.'^, upper and lower, are to each other as 

 13. 16-2, agreeing very nearly with those in H. agilis, H. ulahatus, 

 H. stigmaticus, and 0. frenata. 



No gradations in size connect this species, which is rather 

 numerously represented, with P. azael, to which it stands in much 

 the same relation as does S. otuel to S. yoliah; its inferiority in 

 this respect is therefore characteristic. Not only so, but the 

 differences between two of its dimensions and the corresponding 

 dimensions in P. azael transcend the range of individual variation 

 in size which on the testimony of living Macropods can be allowed 

 within a species. The mean widths of m."' in the two are 13 and 

 18, or an excess in the latter approaching one-half of the former. 

 The greatest living difference is found in P. penicillata, where it 

 amounts to a third only; in H. dorsalis and H. loilcoxi it is still 

 less. Again, the mean anterior depth of the mandible in P. 

 IKtrvus 44*4 is in P. azael increased by more than one-half, and 

 this far exceeds the nearest living approach to it which occurs in 

 H. dorsalis where it is considerably less than one-half. Finally, 

 the premolars (^f P. parvus are relatively much larger than those 

 of P. azael. 



