96 THE ROYAL SOCIETY OF CANADA 



The neural spines, except the fourth, are coalesced and form a 

 low, narrow plate. 



The bases of the diapophysial laminae are so expanded fore and 

 aft as to overlap the preceding and succeeding ones and coalesce, 

 forming a broad base which roofs over the very broad neural canal. 



The neural canal is very much enlarged as in Stegosaurus. It is 

 bordered above by the neural arches and below by the centra. It 

 has a breadth of 71 mm. and a height of 55 mm. in the first true 

 sacral. As in Stegosaurus its anterior portion is largest. The posterior 

 portion is circular with a diameter of about 14 mm. 



Large foramina bounded above by the diapophysial laminae and 

 below by the expanded bases of the sacral ribs furnished exits from 

 the chamber for the nerves. They lead into the large sacral foramina 

 which are not connected with one another by openings through the 

 laminae. 



The caudo-sacral is short, broad, and low, with well-developed 



lateral processes which are expanded distally for articulation with 



the ilium. It is not coalesced to the true sacrais. The neural spine 



■ is partly broken away but seems to have been low. The zygapophyses 



are small. 



The caudal vertebrae are short and broad, indicating a short 

 stout tail. There is one nearly perfect centrum which very closely 

 resembles the one figured by Brown^^ as the ninth caudal of Ankylo- 

 sauriis magniventris (Brown). The anterior face is flat and the 

 posterior face slightly cupped. The bases of the neural arch, lateral 

 processes, and chevron are thoroughly coalesced to the centrum. All 

 of the chevrons, however, were not coalesced to the centra, as shown 

 by one well preserved, free chevron which, judging from its size, is 

 anterior to the one above mentioned. 



Ribs. — The first two cervical ribs on the right side are in the rock 

 and articulated to the atlas and axis. The second cervical rib of the 

 left side (Plate I, Figure 3) is free while the first is coalesced with the 

 centrum (Plate I, Figure 1). 



The first ce.rvical rib is short and stubby. The proximal end is 

 broadly expanded and from this end it narrows and thickens toward 

 the distal end which is obtuse. Like the first cervical rib of Stego- 

 saurus, Ankylosaurus and the crocodile, it is articulated by a single 

 head to the lower posterior border of the centrum. 



The second cervical rib is a tri-radiate bone formed by a long, 

 stout, tubercular process, a short capitular process, and a pointed 

 posterior branch. The proximal end of the tubercular process is 

 " Bull. Amer. Mus. Nat. Hist., vol. XXIV, Feb., 1908, p. 19-5, Fig. 13. 



