116 R. S. Lull — Cretaceous Armored Dinosaur, 



exhibits a number of the ridge-enclosed muscle areas 

 mentioned above. One ridge arises from the region of 

 the great trochanter and descends somewhat obliquely 

 two thirds the length of the bone. It is separated 

 externally by a wide, shallow, oblique groove from a 

 second muscular area on the antero-external face of the 

 bone. The internal condyle is the larger of the two when 

 viewed from the rear. In front they are more nearly 

 equal and the inner one is defined by a narrow curved 

 groove which arises on the inner face of the femoral 

 shaft and runs obliquely down between the condyles. Pos- 

 teriorly the external condyle, as in Hoplitosaurus, while 

 having a somewhat greater fore-and-aft diameter than 

 the internal one, is nevertheless very much narrower, 

 especially toward the distal end of the bone, thus forming 

 a deep vertical notch between the external surface of the 

 condyle and the remainder of the articular surface (see 

 ^g. 5 B and C, n). Above the condyles the shaft bears 

 a rather deep ovoid depression, above which the surface 

 of the bone exhibits an interwoven fibrous surface 

 resembling the textile character of the dermal ossicles 

 which suggested the specific name of the animal. A cross- 

 section of the mid-shaft has a somewhat trihedral form, 

 being flattened on the posterior aspect. 



Tibia, (pi. IV, &g. 5; text ^g. 6).— The left tibia is 

 approximately entire, although the two halves were -not 

 together nor were there definite '^ contacts'' between 

 them. The bone may therefore have been somewhat 

 longer originally, but could not have been shorter. The 

 distal half of the right tibia is also present, together mth 

 a portion of the proximal articular extremity. There is 

 a chance for error in the orientation of proximal and 

 distal halves, but the surfaces curve into one another 

 fairly, so that the error is probably not great. As 

 restored, the long axes of the articular ends make a 

 greater angle. with each other than in Stegosaurus, and 

 the curvature of the bone is somewhat greater. Proxi- 

 mally, the bone is expanded and narrows rather rapidly 

 mto the shaft, to expand again distally. The distal 

 extremity is more flattened in one diameter (antero- 

 posterior) than is the proximal, and the astragalus is so 

 closely anl^ylosed with the bone as to be almost undis- 

 cernible, forming a smoothly rounded though somewhat 

 pitted articular face (see above). In Stegosaurus the 

 astragalus, while coalescing with the tibia with age is 



