122 R. S. Lull — Cretaceous Armored Dinosaur, 



Keeled plate. — One keeled plate free from its attach- 

 ment is associated with the Nodosaurus specimen (pi. I, 

 fig. 4). It is similar to those of Ankylosaurus, Hoplito- 

 saurus (Gilmore 1914, ^g. 70), and Hierosaurus (Wi eland 

 1909, fig. 5), and measures 143 mm. long by 99 mm. wide 

 and 27 mm. high. This plate was one of a pair from the 

 left side of the body, and probably came from near the 

 base of the tail. It is almost the counterpart in size and 

 appearance of the Hierosaurus element shown by 

 Wieland in his figure 5, except that in the Nodosaurus 

 plate the keel is lower, due in part to its having been 

 broken away. 



Caudal plate. — Yet another plate of a similar character, 

 except that it rises to a point at one end instead of 

 bearing a keel, is associated in an inverted position with 

 caudal 17 and must have formed one of a row which lay 

 on either side of the mid-line along the dorsal surface of 

 the tail. The under surface is concave, especially under 

 the above-mentioned point. Above, it is pitted and also 

 bears vascular grooves. Subdermal ossicles apparently 

 underlay it, as they now lie between it and the spinous 

 process of the caudal. 



Measurements of Caudcd Plate. 



mm. 



Length 77 



AYidth ; 59 



Height 19.5 



Spine-like plate.-^Thi^ element, while incomplete, is 

 very suggestive of the dermal plates of Hoplitosaiirus as 

 figured by Gilmore on his plate 30, and also that of 

 Hierosaurus shown by Wieland on his figures 3 and 3a 

 (1909). Similar plates are also associated with Pola- 

 canthus and gave the reptile its generic name. Nopcsa 

 (1905, pi. 12) figures such elements along the presacral 

 vertebrae, a row on either side. In Nodosaurus, this 

 element is large, w^ith a somewhat elliptical base and two 

 sides concave in their vertical diameter and convex fore 

 and aft. The basal portion is ill preserved, but was in 

 part at any rate highly rugose. The lateral faces 

 resemble the limb bones in their surface texture, but were 

 impressed with shallow vascular grooves. The size is 

 greater by far than that of the plate of Hierosaurus and 

 its fore-and-aft diameter exceeds that of Hoplitosaurus. 



