NO. L'lio. .1 \EW RESTORATION OF 8TEG0SAURUS—GILM0RE. 357 



was studying the Stegosaurs. It came into my hands for the first 

 time a few days after the model was finished, and it was particuJarly 

 gratifying to find that independent work should bring such close 

 agreement in the final results. It also explains one of the difficulties 

 encountered in making some of the earlier restorations where the 

 body is obviously too long. This was brought about, apparently, by 

 placing the largest plate of the series above the pelvis, which neces- 

 sitated lengthening the body in order to have space for the plates 

 wliich have been found in place in advance of it. In the model the 

 presacral region is relatively shorter than has been represented in 

 earlier restorations, but since it is based upon careful measurements 

 made from the entire presacral series, it will be seen there is good 

 reason for this shortening, and it is therefore in perfect accord with 

 the evidence for the present position of the dermal armor. The 

 angulation of the occipital condyle in relation to the longer axis of the 

 skull in Stegosaurus is such as to cause the nose of the skull to be 

 depressed if the articulated condyle is to be in line with the cervical 

 vertebrae. While this pose allows of further depression and also of 

 elevation of the nose^ it would appear to be the more characteristic 

 position, as shown in the model. 



At this time the character of the skin covering of Stegosaurus is 

 wholly conjectural, but from what is now known of the integumen- 

 tary covering of some members of the Ceratopsian and Trachodont 

 dinosaurs it is not unreasonable to expect that of Stegosaurus to be 

 scale-Uke, with numerous bony skin ossicles scattered over the sides 

 of the body, as indicated in the model. In the light of recent dis- 

 coveries, we may yet hope to have definite knowledge as to its true 

 nature. 



The head and neck, the massive fore and hind limbs, and in fact 

 the whole appearance of the animal indicate slow locomotion on aU 

 fom- feet. The exceedingly small and feeble teeth would appear to 

 indicate that Stegosaurus must have fed upon the most succulent of 

 terrestrial plants. The feet are large, as though to support the 

 creature's weight on yielding soil. Their structure impHes that they 

 were land-haunting, doubtless of low, swampy regions rather than 

 the upland, but they also suggest being adaptations from a group 

 highly speciahzed for locomotion upon land, and there is every reason 

 to believe that Stegosaurus was descended from a bipedal ancestry. 

 Increasing bulk and development of the armor caused them to lose 

 celerity of movement, and they became sluggish, slow-moving crea- 

 tures, of low mentality, only sufficient, perhaps, to direct the mere 

 mechanical functions of life. 



EXPLANATION OF PLATE 52. 



Model of Stegosaurus stenops Marsh based upon the type skeleton, Cat. No. 4934 U. S. 

 National Museum. Right side. About ^nat. size. Modeled by Charles W. Gilmore. 



