2 
MUSEUM BULLETIN NO. 12 
The above type material is regarded as representing an 
undescribed generic form of Ceratopsia to which the name 
Eoceratops is now given. 
Eoceratops appears to be a generalized type with an occipital 
crest or neck-frill resembling that of Triceratops in the broad 
triangular squamosal but differing very decidedly therefrom 
in the presence of long fontanelles. An approach to Triceratops 
is also found in the enlarged supraorbital horn-core and in the 
formation and position of the small, forwardly directed nasal 
horn-core. 
It is thought, as the name for the genus suggests, that 
Eoceratops was a form ancestral to Triceratops, representing 
an evolutionary stage of the Ceratopsia leading to the later 
and culminating types (Triceratops and Diceratops) with 
immense brow-horns. 
The characters of Eoceratops may be summarized as fol- 
lows: skull small, short, compact; supraorbital horn-core moder- 
ately large, slender, overhanging the orbit, circular in cross section, 
tapering to a point and directed upward, and slightly inward 
and backward above; nasal abbreviated and deep; nasal horn- 
core short, contributed to by the nasals and two separate, 
anterior ossifications; crest or neck-frill slightly longer than half 
the total length of the head; squamosal broadly triangular, 
longer than broad, with a smooth, undulating outer border, 
without epoccipitals, forming the greater part of the crest 
laterally ; fenestrse of the crest long, enclosed without by the squa- 
mosal, and behind by a slender parietal bar which passes for- 
ward beneath the inner posterior border of the squamosal; 
dentary robust, with about twenty-five vertical series of teeth. 
In the restoration outline of the skull given in Plate I, the 
parts of the one individual constituting the type material are shown 
by continuous lines; the parts restored are in broken outline. 
A right maxilla (Cat. No. 285) thought to belong to Eoceratops 
has been used in the restoration of the skull. It was found 
separately about 3 miles below the' mouth of Berry creek 
and cannot be positively referred to this species. From the 
elements represented the length of the skull is approximately 
obtainable, the unrepresented parts necessary for the determin- 
