EOCERATOPS CANADENSIS. 
19 
A final result is reached in the Eoceratops and Chasmosaurus 
groups in a neck-frill of increased compactness, strength, and re- 
sisting power. 
The genera included in the Centrosaurus group are all from 
the Belly River formation so that this group does not furnish 
a representative from the higher horizon in the Cretaceous in 
which Triceratops and Torosaurus occur as culminating types 
of their respective groups. This later form, if such an one 
existed, would probably furnish additional evidence of the at- 
tainment of somewhat similar results through different evolu- 
tionary stages. 
The ancestral type of ceratopsian, presumably belonging 
to early Cretaceous or Jurassic times, from which the Belly 
River Cretaceous homed-dinosaurs descended, had, in all likeli- 
hood, a poorly developed neck-frill contributed to by small squa- 
mosals and a slender parietal framework which together enclosed 
fenestrae of comparatively large size (Plate II). This frill may 
have resembled in a general way the somewhat similarly placed, 
but differently constructed backward prolongation of the skull 
of the living Chamaeleon vulgaris. 
It is thus seen that distinctive characters are found in the 
neck-frill in these three groups of homed dinosaurs. With 
these are linked other definite characters pertaining to the 
brow and nose-homs as already tabulated. 
In the Eoceratops group there is an increase in the size of 
the brow-horns, with a continuance of a small nasal horn, and 
broadly triangular squamosals (Plate V). 
The new genus 1 Anchiceratops of Brown founded on the 
posterior half of a skull from the Edmonton formation on Red 
Deer river, Alberta, belongs apparently to the Eoceratops 
group. In this genus the brow-horns are large, the squamosals 
are broadly triangular and of moderate length, and the frill- 
openings are reduced in size. In the Ceratopsia a well developed 
nasal horn-core accompanies small supraorbital horn-cores, 
and when these latter are large the former is reduced, accordingly 
the nasal horn-core of Anchiceratops ornatus t the type and only 
1 Bull. Amer. Mus. Nat. Hist., Vol. XXXIII, art. XXXIII, pp. 539-548. 
