FOSSIL VERTEBRATES FROM SAN PEDRO VALLEY—GAZIN 511 
were of the normal modern type. The difference from S. medius 
in this respect is not obvious as the teeth in No. 10513 show very little 
wear and are fractured, hence not easily compared with those of the 
S. medius specimen. 
ONDATRA sp. 
A second left upper molar in the Curtis ranch collection was re- 
ferred by Gidley to Neofiber, probably because of its small size, but 
since the enamel folds terminate at the lower end, with the formation 
of small pockets, suggesting a rooted type of tooth, the specimen 
probably represents a form of Ondatra. The tooth is nearly as small 
as that in Ondatra idahoensis * material from the late Pliocene of 
Idaho, but appears to be a little more hypsodont. 
A poorly preserved lower jaw, including a portion of the second 
cheek tooth was found at the Curtis ranch locality in 1936. Except 
for its smaller size the specimen resembles jaws of Ondatra zibethica; 
however, the jaw seems relatively shallow and the anterior margin of 
the ascending ramus extends forward as a ridge to a point nearer the 
anterior end of the tooth row. 
Order LAGOMORPHA 
LEPUS sp., near LEPUS CALIFORNICUS Gray 
A portion of the right mandibular ramus, U.S.N.M. No. 16619, in- 
cluding P; to M,, collected in 1936, is from a lagomorph very near 
Lepus californicus eremicus in size and proportions of the teeth. 
The anterior wall of the posterior column of the lower cheek teeth 
seems somewhat more crenulated than in the modern form. Ps ap- 
pears relatively broad posteriorly and does not exhibit so flattened a 
lingual wall. 
Cf. SYLVILAGUS sp., near SYLVILAGUS FLORIDANUS (Allen) 
A fragmentary right ramus of the mandible with P; and P,, No. 
10528, which Gidley referred to as Species No. 3 and compared with 
Lepus californicus eremicus, is relatively small and more nearly re- 
sembles material belonging to Sylvilagus floridanus. Ps in this speci- 
men exhibits an unusually deep fold from the middle of the posterior 
wall of the anterior column forward into the anterior column, more 
pronounced than shown in Gidley’s figure of this specimen (1922, fig. 
13). 
s5R. W. Wilson, Carnegie Inst. Washington Publ. No. 440, pp. 132-135, 1933. 
