OSTEOLOGY OF THE AKMOKED DINOSAUKIA. 



49 



Fig. 17.— Postekior cervical teetebka op Stegosaukus totgulatus? 

 Maksh. Cat. no. 7348, U.S.N.M. }N,it. size. 1, Side view. 2, Obuque 

 front view, i, diapophtsis; 11, neural canal; p, parapophysis; s, neu- 

 RAL spine: Z, ANTERIOR ZTGAPOPHYSIS; Z', POSTERIOR ZTGAPOPHYSIS. 



The 



The prezygapophyses are wide apart and considerably raised above the 



diapophyses in the anterior vertebrae, but brought more to their level in the posterior 



cervicals. 



Neural spines are not 



present, except in the most 



posterior cervicals, although 



there is a weak, median, crest- 

 like ridge, which eventually 



develops into a true spinous 



process. On account of the 



damaged condition of these 



processes I am unable to 



determine the first vertebrae 



having such a process. 



Dors ally the neural arch 



consists of a broad, trans- 

 versely rounded surface 



which extends upward and 



backward, the posterior 



termination giving off the divergent branches of the post-zygapophyses. 



height of the arch gradually increases posteriorly. 



Dorsal vertebrae {T^xQs&.Q,va\.s 11 to 26).' — The dorsal vertebrae of Stegosaurus are 



characterized by the great height of the neural arch and the upward thrust of the 



transverse processes. The 

 centra of the posterior half of 

 the vertebral column are trans- 

 versely compressed, being shal- 

 lowly concave antero-poste- 

 riorly and somewhat flattened 

 vertically. All of the vertebrae 

 are without lateral cavities. 

 In the anterior dorsals the 

 depth of the concave articular 

 ends of the centra exceeds that 

 of the posterior ends, but pos- 

 terior to the median dorsal 

 region the two ends are sub- 

 equal in this respect. 



In the table of measure- 

 ments on page 53 it will be 



FIG. 18.-ANTERI0R DORSAL VERTEBRA OP f^^^^^^'^^^^'-^^l^^^^-. obscrvcd that the ccutra grad- 



z, ANTERIOR ually incrcaso in length from 

 the thirteenth to the twentieth, 

 the latter being the longest of the entire vertebral series in No. 4934. From this 



point posteriorly they gradually decrease in length to the sacrum. 



1 All through the text and legends to the illustrations, the presacrals are numbered from the skull toward the sacrum, and 

 not from the sacrum forward as is the usual procedure in referring to the vertebrae as presacrals. 



U.S.N.M. i Nat. SIZE. 1, Side view. 



n, NEITRAL canal; P, PAR.AP0PSYSI3; S, NEURAL SPINE; 

 ZTGAPOPHYSIS; z', POSTERIOR ZTGAPOPHYSIS. 



