HOODED HADROSAURS OF THE BELLY RIVER SERIES OF THE 
UPPER CRETACEOUS: A COMPARISON, WITH 
DESCRIPTIONS OF NEW SPECIES 
By C. M. Sternberg 
CONTENTS 
Comparison of Belly River forms 
Corythosaurus exeavatus ; 
Corythosaurus intermedius 
Tetrcigonosaurus cranibrevis sp. nov. . . 
Lambeosaurus clavinitialis sp. nov 
Lambeosaurus magnicrislatum sp. nov. 
Comparative measurements 
References cited 
Page 
. 4 
. 4 
. 12 
. 13 
15 
. 20 
. 22 
. 23 
Illustrations 
Plates I-m. Corythosaurus exeavatus 25-29 
IV. Teiragonosaurus cranibrevis and Lambeosaurus clavinitialis 31 
V-VI. Lambeosaurus clavinitialis 33-35 
VII. Lambeosaurus magnieristatum 37 
Figure 1. Cross-section (natural size) of left premaxilla of No. 8676 taken through 
the back of the open slit. L.P.— lower air passage; U.P,=anterior part of 
upper air passage 7 
2. Corythosaurus exeavatus Gilmore 9 
The hooded hadrosaurs were the most diversified and perhaps the most 
specialized of the Upper Cretaceous duck-billed dinosaurs. Lambe was 
the first, in 1914, to describe a helmet-crested or hooded hadrosaur, when 
he figured a skull and lower jaw as Stephanosaurus marginatum (7). A 
few months later Brown described a beautifully preserved specimen of 
hooded hadrosaur as Corythosaurus casuarius (2). He believed that 
Lambe was not justified in referring his new skull to Stephanosaurus mar- 
ginatum and stated that the two skulls were probably congeneric. 
In 1920 Lambe proposed a reclassification of the Hadrosauridae and 
removed the various hooded hadrosaurs from the Saurolophinae to a new 
subfamily Stephanosaurinae (10). He then described and figured a well- 
preserved skull as Stephanosaurus marginatus and showed for the first time 
that the hood was made up of the premaxillary and nasal bones and that 
the narial passages lead up into the hood. 
In 1923 Parks, from a study of the literature, concluded that it had 
not been shown that the helmet-crested skulls that Lambe described 
were co-specific with Stephanosaurus (Trachodon) marginatus and, accord- 
ingly, that they were without generic or specific name. He proposed the 
new name Lambeosaurus lambei for the skulls and, presumably, regarded 
the better skull, Cat. No. 2869, Geol. Surv., Canada, as the type. At the 
same time he proposed the new subfamily name Lambeosaurinae to 
replace Lambe’s Stephanosaurinae (14, pages 7-8). Gilmore, after a careful 
