EOCERATOPS CANADENSIS. 
11 
The genus Ceratops, Marsh, is defined in Hatcher’s memoir 
on “The Ceratopsia,” page 100, as follows : “The present genus 
may be distinguish^! from Monoclonius, Cope, based on material 
from the same beds in Montana, by the greater development of 
the supraorbital horn-cores, the longer and narrower squamosals, 
the enlarged fontanelles, by which the parietals are reduced to 
slender median and lateral bars. The nasal horn-cores are very 
probably quite different also in the two genera, though we cannot 
as yet be certain as to their character in Ceratops . From our 
present knowledge of the skull of Ceratops it seems to have been 
a precursor of Torosaurus , Marsh, while Monoclonius , Cope, 
appears to have been ancestral to Triceratops , Marsh.” 
As the material on which Ceratops montanus , the type of 
the genus, is based consists of a pair of supraorbital horn-cores 
and an occipital condyle, no other parts of the skull (and nothing 
of the rest of the skeleton) being known, the above characters 
assigned to the squamosals, and the parietals and their openings 
are hypothetical. Mr. Hatcher in his monograph, page 97, ex- 
pressed his conviction as to the generic identity of Eoceratops 
{Monoclonius) canadensis and Chasmosaurus ( Monoclonius ) 
belli with Ceratops montanus and no doubt it was this view 
which led him to assign characters to Ceratops for which there 
was no warrant in the generic type. 
In 1897 the writer collected in the Belly River formation, 
Red Deer river, Alberta, a left supraorbital horn-core (Cat. 
No. 254) which more nearly resembles those of Ceratops montanus 
in its general shape, and forward and outward curvature, than 
those of any other ceratopsian of which he has any knowledge. 
At present the characters of the genus Ceratops, Marsh, 
are not sufficiently definable and it will be necessary to await 
the discovery of further material before its relationship to known 
members of the Ceratopsia can be satisfactorily determined. 
In Eoceratops canadensis, of which the principal diagnostic 
parts of the skull are known from excellently preserved material, 
the brow-horns are very different in shape and curvature from 
those of Ceratops montanus and it is reasonable to suppose that 
the skull of the latter when found will exhibit strong distinctive 
characters. 
