102 R, S. Lull — Cretaceous Armored Dinosaur, 



giving thus a broad bearing surface for the armor, 

 although, as has been shown (Gilmore, p. 64), this type of 

 rib is not confined exclusively to the armored forms. 

 The lateral expansion of the rib begins as a low ridge 

 about midway between the capitulum and tuberculum. 

 The prezygapophyses overhang the centrum forward to 

 a marked degree. The spinous process is thin, but has 

 a marked fore and aft extent, with a straight superior 

 margin. This may be seen from above where the armor 

 is broken away, and exhibits little if any lateral expan- 

 sion, being simply a thin plate of bone, narrowing slightly 

 toward its posterior end. The spinous process over- 

 hangs the postzygapophyses, so that while obscured by 

 matrix, its outline must have approximated that shown 

 in the figure (text fig,. 2). The outline of the bone seems 

 to have resembled quite closely that of Ankylosaurus as 

 figured by Brown (1908, ^g. 11) ; it is also suggestive of 

 Stegosaurus, but without the exaggerated heightening of 

 the neural arch of the latter. Calcified tendons are 

 present, lying close to and on either side of the spinous 

 process. Those present diverge somewhat posteriorly. 

 They are heavy and quite rib-like in appearance, except 

 for their orientation and lack of curvature. 



Measurements of Presacral Vertehrce. 



mm. 



Length over all 130 



Height over all, est 220 



Centrum, length 88 



Neural canal, width 13.5+ 



Width across pedicels 56 



Width across prezygapophyses .... 68 



Width across diapophyses 152 



Spinous process, length of summit. . 66 



Calcified tendon, width 14 



Calcified tendon, depth 15.8 



Pelvis. 



(Pis. II, III.) 



Sacrum. — The sacrum of Nodosaurus consists of three 

 sacral vertebrae in the primary sacrum, and, as preserved, 

 of at least four coalesced presacrals (sacro-lumbars) and 

 two sacro-caudals, making a total of nine vertebrae in the 

 entire syn-sacrum complex. The centra are so firmly 



