FOSSIL VERTEBRATES FROM SAN PEDRO VALLEY—GAZIN 491 
S. minor and 8. curtisi. S. medius is characterized by being more 
brachydont than modern forms, hence the appearance of somewhat 
more open valleys and compressed ridges. The anterior reentrant on 
the lingual surface of the first lower tooth is deeper than the outer 
in the type, as was noted in certain material of S. sanctae martae, but 
the anterior lobe is distinctly narrower than in modern material. 
Perhaps the most significant character in the lower teeth is the depth 
of the posterior reentrant on the lingual surface of the second cheek 
tooth, a distinct notch being present in this position on the third tooth. 
This reentrant and perhaps the notch, however, are not so well de- 
veloped as in material of Holochilus from Argentina. Moreover, the 
posterior portion of the linqual wall of the third cheek tooth makes 
a sharp angle with the posterior wall of the lingual reentrant, this 
angle being more rounded in S. hispidus material. 
In the upper cheek teeth of the type the anterior lobe of the first 
is narrow as it is in the lower teeth, and as noted by Gidley the 
external reentrants appear a little more arcuate in an occlusal view. 
NEOTOMA FCSSILIS Gidley 
The type of Veotoma fossilis is a right maxillary portion, No. 19524, 
with the first cheek tooth preserved and showing the alveoli for the 
second. ‘To this were referred two right lower cheek teeth, No. 10526, 
and the greater portion of a left lower jaw, No. 10525, exhibiting the 
incisor but no cheek teeth. 
The first upper cheek tooth in the type is about as wide as in Veotoma 
cinerea but distinctly shorter and lacks the anterointernal fold on the 
anterior column. The lower teeth referred are also relatively short 
and wide, and again, the first of these lacks the fold on the antero- 
internal surface of the anterior column. Possibly a less deeply im- 
pressed anterointernal fold may have been present in first upper and 
lower cheek teeth at an earlier stage of wear, but these cannot have 
been developed to the extent seen in some of the modern material. 
Both the upper and lower teeth are well worn so that the reentrants 
are compressed; however, the posteroexternal of these in the lower 
teeth is somewhat more open and more noticeably pocketed than 
the others, a condition markedly developed in material of Veotoma 
magister from Cumberland Cave. Moreover, as Gidley indicated, the 
cross lophs of the lower teeth, particularly the second, are noticeably 
oblique; however, this may in part be due to the stage of wear repre- 
sented together with the greater vertical depth and open character 
of the posteroexternal folds and the depth of the anterior of the two 
internal folds. 
® J. W. Gidley and C. L. Gazin, U. S. Nat. Mus. Bull. 171, pp. 59-60, 1938. 
469725—42 3 
