A. Cervical vertebra? long; median horn-like processes anterior
to the orbit; nasal tuberosities do not overhang
the nasal tips.
(_a_) Last molar, with or without a tubercle, occupying
the entrance of the valley between the lobes,
and but one on posterior basal ridge. Temporal
fossæ not continued beyond the base of the
parietal processes. Occipital condyles projecting.
_Uintatherium._
(_b_) Last molar never has a tubercle at entrance of
valley, and has two on posterior basal ridge.
Temporal fossæ continued very far back; condyles
sessile. _Dinoceras._
B. Cervical vertebræ short; median horn-like processes
directly over the orbit; nasal tuberosities overhang the
entire tips. _Loxolophodon._