Sinclair: marsupialia of the santa cruz beds. 429 
molars, as well as the alveoli of the canine, the anterior premolar and the 
first molar. 
The species may be recognized by its size, by the presence of dias- 
temata between the premolars, by the spacing of the canine and anterior 
premolar, and the single-rooted condition of the latter tooth. 
Fig. 8. 
Palceothentes aratce, right ramus, x f . From an enlarged photograph of a specimen in the 
Ameghino collection. 
The mandible, shown in the accompanying figure (text fig. 8), drawn 
from a photograph of a jaw in the Ameghino collection, is very heavy 
and deep, with convex lower border. The horizontal ramus increases 
slightly in depth posteriorly. 
Measurements. 
fj 
ti 
a 
u 
Length, posterior border of canine alveolus to MT inclusive 
of space occupied by premolars 
“ “ ,f “ molars 
Median premolar, antero-posterior diameter 
“ “ transverse 
Posterior premolar, antero-posterior 
“ “ transverse 
M- 2 -, antero-posterior diameter 
“ transverse “ 
M- 2 -, antero-posterior “ 
“ transverse “ 
M^, antero-posterior diameter 
“ transverse “ 
Posterior lower premolar, antero-posterior diameter 
Length of inferior molar series on alveolar border 
M t , antero-posterior diameter .... 
M ff , “ 
Amegh. Coll. No. 954.9. 
•0235 
.0125 
.0115 
.0025 
•0015 
.006 
•0035 
•0035 
•005 
.0025 
•0035 
.002 
.0025 
•0035 
.015 
.0065 
.004 
