14 
Fortunately there are no less than three nearly complete articulated 
skeletons known of Thespesius annectens (Marsh) : the type, No. 2414, in 
the United States National Museum, Washington, D.C.; the paratype, 
No. 2182, in the Yale Peabody Museum, New Haven, Conn.; and a referred 
specimen, No. 5060, in the American Museum of Natural History, New 
York. None of these has been fully described, though they are sufficiently 
well known to afford a basis of comparison for the specimen now under 
consideration. 
After careful study and comparison, I find that except for the 
presence of thirty-two presacral vertebrae in the Edmonton specimen, as 
contrasted with thirty in the Lance Thespesius annectens as originally 
determined by Marsh 1 , there appears no reason why all these specimens 
should not be regarded as belonging to the same genus. This important 
difference in these otherwise closely allied forms is not to be accounted 
for by a reduced number of sacral vertebrae, for there are nine in each of 
the typical specimens. In all probability, as I shall attempt to show later, 
it is due to the mistaken idea of Professor Marsh that he was dealing with 
complete, articulated specimens in which none of the presacral vertebrae 
was missing. If such an important structural modification cannot be 
thus explained, it affords a most unusual difference in animals that are 
otherwise strikingly alike. Awaiting further evidence to clear up this 
uncertainty, this specimen from the Edmonton formation is provisionally 
regarded as belonging to the same genus as the Lance specimens first 
described by Marsh under the name of Claosaurus annectens . 2 Differences 
in the proportions of the fore limbs, and structural peculiarities in the 
manus indicate it to be a distinct species, for which the name Thespesius 
edmontoni is proposed. 
Family, Hadrosaurid^e Cope 
Sub-family, Hadrosaurince Lambe 
Thespesius edmontoni new species 
PLATES II, III, IV, AND V 
Trachodon marginatus, Lambe, L. M., Ottawa Naturalist, vol. 27, 1913, 
pp. 21-25, Plates II, III. 
No Name , Lambe, L. M., Ottawa Naturalist, vol. 27, 1914, p. 135, 
Plate 17. 
Type: No. 8399, Geol. Surv., Can., consists of an articulated skeleton, 
complete back to the sixth caudal vertebra. Ossified tendons and skin 
impressions. Collected by C. H. Sternberg, 1912. 
Locality: Sec. 30, tp. 29, range 19, W. 4th mer., on Michichi creek, 
5 miles from Drumheller, Red Deer river, Alberta. 
Horizon: Edmonton formation, Upper Cretaceous. 
Generic and Specific Characters: Skull long, moderately high, narrow 
posteriorly, concave in frontal region. Beak moderately expanded, 
recurved. Anterior nares confluent. Narial orifice strongly defined. 
Numerous rows of teeth, usually without papillate borders; enamel faces 
short. Pocket-like recess in postorbital, small. Mandibular ramus not 
1 U.S. Geol. Surv., 16th Ann. Kept., pt. I, 1896, p. 222. 
* Am. Jour. Sc., 1892, p. 453, Fig. 4. 
