Sinclair: marsupialia of the santa cruz beds. 
43i 
No. 
15,225. 
No. 15,925. 
No. 9550. 
Posterior premolar, antero-posterior diameter. 
.0043 
.004 
.004 
“ “ transverse diameter 
.0023 
.0022 
.0022 
Mb antero-posterior diameter 
.004 
.0038 
.004 
<f transverse “ 
.0032 
.003 
.0033 
Mb antero-posterior “ 
.0025 
.0025 
.0028 
“ transverse “ 
.0032 
.003 
• 0033 
Mb antero-posterior “ 
.0017 
.0018 
“ transverse “ 
.002 
.002 
Mb antero-posterior “ 
.001 
.001 
“ transverse “ 
Greatest interorbital width . 
.0013 
.0105 
.0012 
Least width of brain-case .... 
Greatest breadth of nasals .... 
Depth of skull to alveolar border at front of 
orbit ....... 
Width of palate between anterior premolars . 
“ “ “ at Mi 
“ “ “ “ M^- 
.007 
.0087 
.007 
.010 
.010 
Pal^eothentes lepidus Ameghino. 
(Plate LXII, Figs. 6, 6a.) 
Epanorthus lepidus Amegh. ; Revista Argentina, I, p. 305, 1891. 
This species is known only from the mandible, of which the American 
Museum collection contains four incomplete specimens (Nos. 9596-9598, 
9600) found by Mr. Brown on the Rio Gallegos. 
In size P. lepidus is intermediate between P. niinutus and P. interme- 
dins. The vestigial teeth occupy a shorter space than in P. minutus and 
are more closely crowded. The alveoli of the first and second are larger 
than those of the third and fourth, are closely adjacent and strongly 
inclined forward. The alveoli of the third and fourth vestigial teeth are 
approximately vertical. 
The mental foramina vary considerably in size and relative position and 
are of little diagnostic value. The principal measurements agree closely 
with those of a natural-size photograph of the type in the Ameghino col- 
lection, and have been depended on largely for the correctness of the 
specific identification. 
