[lambe] PANOPLOSAURUS MIRUS 45 



somewhat more glossy appearance, best seen in weathered specimens. 

 In a number of scutes belonging to the type the spur or posterior 

 termination of the keel is defective owing apparently to imperfect 

 ossification. 



In the type specimen two large keeled scutes, corresponding to 

 each other in size and shape and belonging one to either side of the 

 neck, have a length equal to 2% the breadth at midlength. Length 

 about 230 mm., breadth about 86 mm. 



Also in the type three scutes with high keels are preserved follow- 

 ing each other in natural sequence, and constituting part of a flank 

 row of the right side. The posterior scute of these three has a length 

 slightly over 1^ its breadth at midlength. Length about 173 mm., 

 breadth about 97 mm. The middle one is 162 mm. long, and 97 mm. 

 broad, and the foremost one 115 mm. in length p.nd 84 mm. across. 



In Panoplosaurus the armature of heavy plates and scutes no 

 doubt allowed a moderate flexion of the body, and a free motion of 

 the limbs, but the movements of the animal must have been decidedly 

 slow and deliberate. 



Dorsal Neck Scutes (Plates V, VI, VII, and XII). Two of these 

 scutes and half of a third are preserved. One, found immediately 

 behind the skull, is referred to and described below as the nuchal 

 plate. Another, supposed to be the second of the longitudinal 

 row of the neck, on account of its similarity in size and shape to 

 the nuchal plate, was about two feet to the right of this plate at 

 about the same level. The remaining incomplete plate lay beneath 

 the nuchal one and may be the third of the series. 



The nuchal plate is rather thin, somewhat semi-circular in out- 

 line as seen from above, and broader than long, the length being about 

 three-fourths the breadth. It is bilaterally symmetrical, curving down 

 on either side so as to be transversely concave on the under surface. 

 It is composed of two similar, subtriangular scutes which unite along 

 their inner edge, the line of junction being marked by a deep, straight 

 groove extending down the middle of the upper surface of the plate 

 from the front to the back. Each scute, or half-plate, has a longitu- 

 dinal, low but broad keel on either side of which the upper surface is 

 transversely concave. These keels tend to disappear at the front 

 border and are broadest and most elevated posteriorly. They are 

 placed somewhat obliquely on the scute curving slightly outward in 

 their backward course. The upper surface of the plate is in this manner 

 divided into four nearly equal, longitudinally flat, transversely concave 

 areas so as to have a shallowly fluted appearance. The whole of the 

 upper surface is rough and marked by irregular, shallow vascular 



