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inferred by Schultz and Falkenbach. In addition, an unerupted
bud of permanent p4 would be expected to exist below this
anterior-most tooth if it is the dP4. On the contrary, this
anterior tooth is strongly rooted and well socketed in the
maxillary bone.
Since LACM 1382 represents an adult individual, compar-
ison can be made with the holotype of M. (M.) calaminthus.
This comparison reveals several morphological differences
and an average size difference of 15 per cent.

Order ARTIODACTYLA
Family Merycoidodontidae
Subfamily Merychyinae
I
Merychyus (Merychyus) calaminthus Jahns (restricted)
~: Part of a skull with pl to M3, LA.CM 1383.
Referred material: Badly crushed fragment of left mandible
with P3 to M3 inclusive, LACM 1342.
Type locality: CIT 201; west side of small canyon in south-
west corner of Section 2#~ TSN, RlSW, San Bernardino Baseline
and Meridian, Humphreys Quadrangle (1932), United States
Geological Survey (Jahns, 1940, p. 187).
Amended diagnosis: Size slightly smaller (less than two per
cent) than~- (Merychyus) crabilli Schultz and Falkenbach;
skull apparently with deep antorbital fossa, but prelacrimal
vacuity small, if present; malar depth moderate, single large
infraorbital foramen above p4; dentition hypsobrachyodont,
superior tooth row straight and closely spaced, superior
premolars with fairly complicated patterns, only moderately
reduced anterior lophs of p3-4; pl-2 set at slight angle to
alveolar border; external styles of superior molars moderate-
ly prominent.
Discussion: In addition to the above mentioned characters,
Jahns noted the presence of a small lingual spur projecting
into the fossette in p4. Schultz and Falkenbach attribute
this character to individual variation, however an oreodont
skull fragment in the collection of the University of
California, Riverside, from an undescribed Arikareean fauna
in the Mojave Desert displays this character also. 1~e P3_4
in the referred mandible are well worn, but still bear
remnants of lingual fossettes, suggesting similar complexity
to the upper premolars. Jahns (1940, p. 189-90) also figures

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