EUTRACHYTHERUS Vi 
have been unusually broad and flat. The maxilla extends 
up to the nasals, and bounds the lower border of the orbit, 
and projects backward in a heavy overhanging zygomatic 
process. The lachrymal bone is large externally, with a 
large but low lachrymal tubercle just below which is 
found the lachrymal duct, opening just in front of the 
margin of the orbit. The frontals are short and wide, 
extending outward over the orbit in a strong postorbital 
process which bounds half of the rear of the orbit. The 
parietals, meeting medianly, rise in a strong sagittal crest. 
Unfortunately the back part of the cranium ts lacking. 
Fig. 46. E. spegazzinianus—1/2 natural size. 
From another specimen, which contained the brain cast, 
it is clear that the bulla was much inflated and hollow, and 
that there was an inflation in the upper part of the squa- 
mosum, as in Prosotherium, etc. 
One specimen with the facial portion badly weathered, 
but retaining enough to identify the species as /. spegasz- 
zinianus, preserved the brain case, so that it could be 
prepared out. 
The most striking feature of this brain is its relatively 
large size, E. spegazzinianus being an animal about the 
size of a sheep, and the brain is as large as that of the 
sheep, which is in strong contrast to what would be ex- 
pected of an Oligocene form. Compared with the herbiv- 
