OSTEOLOGY OF THE ARMORED DINOSAUEIA. 125 



A study of the crania in the National Museum shows that in all the occipital 

 condyle is deflected downward in such a way from the longer axis of the skull as 

 to cause the anterior portion of the cranium to be carried low in front if the con- 

 dyle is to be in line with the cervicals. While the articulation is such as to allow 

 of further depression and also of elevation, it would seem that the normal pose 

 would be much as in Camptosaurus, Trachodon, Triceratops, and Diplodocus. All 

 of the pictorial restorations shown in the preceding pages, with the exception of 

 Knight's (pi. 33, lower figure), show the head with an extreme elevation of the nose. 



In the fore feet, as shown by the articulated limb of S. stenops (fig. 40), there 

 is but a single row of ossified carpals, and it appears from the evidence of other 

 feet that the third, fourth, and fifth digits carried a reduced number of phalanges — 

 not a full complement as shown in the Yale skeleton. 



As Lull 1 has pointed out, "The feet are large as though to support the creature's 

 weight on yielding soil, the hand evidently possessing five, while the foot bore 

 three, well-developed digits (and one which is vestigal). The semi-digitigrade 

 feet were doubtless inclosed in a fleshy mass as in the modern elephants, while 

 the external indications of the digits were mainly the hooflike nails." It seems 

 most probable that in life only two of these digits (I and II) were in evidence. 



The body is lank, but I can not agree with Lull that the hips are narrow, for 

 while they do not have the great breadth of the Triceratops pelvis, they are never- 

 theless of good width. 



I would question somewhat the proportions of the skeleton shown in plate 36, 

 lower figure, as being typical of the Stegosaurian dinosaurs. The great elevation of 

 the trunk and tail above the ground is evidently brought about by the unusual 

 length of the femora used in this composite mount. The stilted appearance of 

 this specimen, I am sure, would not be attained by any of the individuals in the 

 National Museum collections. The difference in length between the exceedingly 

 long femora used in the S. ungulatus skeleton and the longest ones before me is 

 well shown in figure 45. 



The great height of the hips brought about a corresponding elevation of the 

 shoulder region which in this specimen necessitated the straightening of the fore 

 limbs almost to their limits in order to articulate them with the skeleton. This 

 does not seem to me to be the normal standing pose, for the presence on the ulna 

 of a large olecranon process and the development of strong rugose processes on 

 the humerus afe features implying a bent, strongly flexed limb of the Ceratopsian 

 type. With shorter femora such a pose could be easily brought about in the 

 mounted skeleton with the resulting advantage of bringing the head nearer the 

 ground, obviously a more natural position, for in the present pose, on account of 

 the short neck, the animal's nose could only have reached the ground with the 

 greatest difficulty. 



The mounting of this skeleton shows the animal as being somewhat shorter 

 than Marsh's estimated length of 25 feet. Lull gives the total length of this speci- 

 men between perpendiculars as 19 feet 5 inches and the greatest height from the 

 base to the top of the highest plate as 11 feet 10£ inches. The latter measurement 



1 Amcr. Journ. Sci., ser. 4, vol. 30, 1910, p. 367. 



