O. C. Marsh— Mammals of the order Dinocerata. 121 
_The vertebrae of this group are not unlike those of Probos- 
cidians in their main characters. The cervicals are materially 
absence of upper incisors. 2d. e€ i 
‘d. The presence of horns. 4th. The absence of large air cavi- 
ies in the skull. 5th. The malar bone forms the anterior 
portion of the zygomatic arch. 6th. The presence of large 
postglenoid processes, 7th. The large perforated lachrymal, 
orming the anterior portion of the orbit. 8th, The small and 
horizontal narial orifice. 9th. The greatly elongated nasal 
bones, . The premaxillaries do not meet the frontals. 
11th. The lateral ree posterior cranial crests. 12th. The very 
on the nasal bones were probably short, dermal weapons, some- 
thing like those of the Rhinoceros, but much smaller. Those 
