98 



BULLETIN 89, UNITED STATES NATIONAL MUSEUM. 



of the plates of No. 4934, as shown in plate 14. Had there been considerable 

 space between them in folding back, the plates of one side would hare their bases 



projecting beyond those of the other, a 

 distance approximately equal to the 

 space between the bases in life. 



The internal lip of the transversely 

 expanded bases of the plates of opposite 

 rows on the neck and anterior dorsal re- 

 gion, inspecimenNo. 4934, appearto have 

 overlapped the median line of the back 

 as shown in figure 61. In other words, 

 the expanded portion of the plates of one 

 row are in the center of the interspace 

 of those of the opposite side, so that the 



Fig. 62.— Section op the trunk of Stegosaurus. d, Dia- 



POPHYSIS; pi, DEBMAL PLATE; r, RIB; S, SPLNE; V, VERTE- 

 BRA. Modified from Lull. 



point where the plates emerged from the 

 thick skin of the back must have been but 

 very Little off the middle line of the back. 



The evidence in favor of an erect 

 rather than a procumbent position for the 

 plates, is shown by the fact that both surfaces are covered with blood-vessel 

 impressions and no indication of either having been in contact with the creature's 



Fig. 63. — Section of the proximal part of the tail 

 of Stegosaurcs. c, Chevron; pi, dermal plate; s, 

 spine; V, vertebra. Modified from Lull. 



