FOSSIL VERTEBRATES FROM SAN PEDRO VALLEY—GAZIN 485 
Mustelid ? sp. 
Gidley (1922, p. 120) indicated in his list of the San Pedro Valley 
faunas the presence of mustelid material in the Benson as well as in 
the Curtis ranch collections. I have been unable to find any specimen 
of this type in the Benson collection, and although it may have been 
lost it is possible that the check in Gidley’s table indicating its occur- 
rence at Benson may have been a misprint. However, Osborn in his 
proboscidean monograph (1936, p. 680) indicated in a list of the com- 
bined San Pedro Valley faunas the presence of material of a small 
species of mustelid in the American Museum Benson collection, pre- 
sumably that made by Gidley in 1924. This too, Dr. Granger in- 
formed me, does not seem to be extant. It is highly probable that 
mustelids were in the Benson fauna, but since this cannot be demon- 
strated the listing of such is queried. 
FELIS sp. 
The distal portion of a humerus and three incomplete toe bones of 
a large cat were found by me near the Benson locality in 1936. The 
portion of a humerus exceeds in size corresponding material of Felis 
concolor in the National Museum collections but can be closely 
matched in one of the jaguar skeletons. The fragment, however, 
shows no important characters allying it to either the puma or jaguar, 
and the entepicondylar foramen differs somewhat from that in both 
in being more slitlike and not so distally placed. 
Order RODENTIA 
CITELLUS BENSONI Gidley 
The ground-squirrel material from the upper Pliocene locality 
near Benson includes the type, No. 10531, consisting of M* (probably) 
and part of P* from the right side and M? from the left, three lower 
jaw portions from different individuals exhibiting one, two, and three 
teeth each, and a few isolated lower teeth. 
Citellus bensoni is a little smaller than C@. (Otospermophilus) 
beecheyi, and the teeth are not of the true Citellus type, in which 
there is a development of high, compressed transverse lophs, but 
correspond more nearly to those in forms belonging to the Otosper- 
mophilus group, in which some character of the individual cusps is 
retained. The lingual portion of the upper teeth, notably M', does 
not appear to be so extended anteroposteriorly with the crests at the 
anterior and posterior margins of the tooth joining the protocone 
without so marked a lingual expansion. The metaconule in M! is 
conical, more clearly separated from the protocone and closer to the 
metacone than in M' of Otospermophilus dentitions, somewhat as in 
