76 
The transverse processes spring from the junction of the centrum 
and the neural arch, and, viewed from the front, stand at almost right 
angles to the centrum, with a slight inclination backwards. 
The lateral and inferior faces are concave and there are two well- 
marked foramina side by side on the inferior surface. On the inferior 
surfaces of the succeeding caudals, except the more distal ones, are two or 
three well-marked foraminse always in a transverse line. 
The sixth caudal of T. saskatchewanensis differs from the type of 
T. occidentalis in being proportionately broader, less concave interiorly, 
and in having the inferior foramina in a transverse line. 
It cannot be stated with certainty that this centrum occupies the same 
position in the series as the one figured by Leidy as the type of T. Occident 
talis , but in none of the caudal centra of specimen No. 8509 is the anterior 
face higher than wide, as it is shown to be in Leidy’s type. 
Though it is fully recognized that these are minor differences it is also 
true that one would not expect great variation, in this region, within the 
genus. Since Lucas has identified T. occidentalis and T. ( Claosaurus ) 
annectens as pertaining to the same species and Gilmore has shown that 
they can not be positively separated, it would seem unwise to refer the 
Saskatchewan specimen, which is clearly distinct from T. annectens, to 
occidentalis. The name saskatchewanensis is accordingly proposed for 
its reception. 
In 1890, Marsh described the right dentary of a hadrosaur under the 
name Trachodon longiceps 1 . The specimen was collected from the Lance 
formation in Niobrara county, Wyoming, and is described as being 3§ feefc 
long. The edentulous portion is 1| feet long; the alveolar border is the 
same length; and there are grooves for fifty-one vertical rows of teeth. 
The great difference in size, proportionate length of edentulous portion 
to length of alveolar border, and the difference in the number of vertical 
rows of teeth of T. longiceps, when compared with T . saskatchewanensis, 
make it clear that these two cannot be referred to the same species, if 
indeed they belong to the same genus. 
Some of the outstanding features in which Thespesius saskatchewanensis 
differs from T. annectens are: skull proportionately higher; quadrate longer 
when compared with the total length of skull; beak broader; enamel faces 
of dentary teeth longer; frontal contributing less to the formation of the 
orbit; and scapula longer and straighter. 
Gilmore recently described a specimen from the Edmonton formation 
under the name of Thespesius edmontom \ Though the skull of the type 
of T. edmontoni is not so well preserved as the Saskatchewan specimen 
and lacks such details as shape and size of teeth and number of tooth rows, 
it shows sufficient differences to preclude the possibility of the two speci- 
mens belonging to the same species. When compared with the skull of 
T. edmontoni the skull of T. saskatchewanensis shows distinct differences, 
of which the outstanding are: skull higher and quadrate longer when 
compared with the length of the skull; beak broader; frontals contributing 
less to the formation of the orbit; orbit less triangular in outline, and 
jugal more slender. 
i Am. Jour. Sci. and Arts, vol. XXXIX, p. 422. 
* Geol. Surr., Canada, Bull 38, pp. 13-28 (1924). 
