March 6, 1924 
Canada 
Geological Survey 
Bulletin No, 38 
GEOLOGICAL SERIES No. 43 
A NEW COE LURID DINOSAUR FROM THE BELLY RIVER 
CRETACEOUS OF ALBERTA 
It has long been recognized by vertebrate palaeontologists that one 
or more undescribed members of the carnivorous dinosauria are present 
in the Belly River fauna, as indicated by certain fragmentary remains 
that have been found from time to time. It was, therefore, of great 
interest to find specimens in the palaeontological collections of the Geolo- 
gical Survey, Canada, sufficiently well preserved to throw some light on 
the character of these unknown forms. The importance of these fossil 
specimens was fully recognized by the late Mr. L. M. Lambe, who, shortly 
before his death, had prepared brief notes descriptive of these materials 
and the drawings that illustrate this paper. 
Before proceeding with the description, it appears in order to review 
briefly the status of certain described forms from the Upper Cretaceous 
formations of North America, so that the reader may more clearly under- 
stand why these specimens are assigned to the family Coeluridse. 
In 1903 1 Lambe founded the new species Ornithomimus altus upon a 
complete right hind limb and foot, articulated phalanges of the left foot, 
a pubis, and an ischium, all of one individual. 
In 1917 2 3 Osborn, on the basis of a beautifully preserved skeleton, 
proposed the new “subgeneric or generic” name Struthiomimus to include 
Lambe’s species Ornithomimus altus. Osborn failed at that time to give 
adequate generic differences for separating it from Ornithomimus, his 
principal argument being that Struthiomimus represented, geologically, a 
distinctly more ancient stage than the Denver-Lance Ornithomimus, and 
that since “The known carnivorous and herbivorous dinosaurs underwent 
profound modifications, it is not probable, therefore, that the Ornithomi- 
midae remained generically unchanged”. Whether Osborn is correct or 
not in these deductions remains to be demonstrated. 
In 1922 s Matthew and Brown described the new genus and species 
Dromceosaurus albertensis, based on a considerable portion of a skull, 
lower jaws, and a few foot bones. Drommosaurus , comparable in size with 
Ornithomimus , was placed in a distinct sub-family, the Dromaeosaurinae 
provisionally referred to the family Deinodontidae. 
1 Contr. to Can. Pal., vol. 3, pt. II, 1902, pp. 50-53, Plates XIII, XIV, XV, Figs. 1-8. 
* Bull. Am. Mus, Nat. Hist., vol. 35, 1917, p. 733. 
3 Bull. Am. Mus. Nat. Hist., vol. 46, 1922, pp. 383-385, text Fig. 1. 
