OSTEOLOGY OF CARNIVOROUS DINOSAURS. 

 Measurements of presacral vertebrae of Antrodemus valens Leidy. 



43 



Vertebrae. 



Greatest length of 

 centra. 



Greatest transverse 

 diameter poste- 

 rior end. 



Greatest height over 

 all. 



Least transverse 

 diameter of cen- 

 tra. 





No. 4734. 



No. 8367. 



No. 4734. 



No. 8367. 



No. 4734. 



No. 8367. 



No. 4734. 



No. 8367. 



Atlas 



mm. 

 28 

 85 

 105 

 102 

 109 

 111 

 115 

 115 

 123 



mm. 



89 

 105 

 106 

 111 

 .121 

 125 

 120 

 122 



mm. 

 60 

 53 

 60 

 75 

 76 

 83 

 95 

 94 

 92 



mm. 



mm. 



mm. 



mm. 



mm. 



Axis 



3 : 



66 



77 



85 



94 



104 



105 



117 



110 



170 



187 



192 



a 188 



195 



215 

 225 

 235 

 247 

 248 

 276 



24 

 36 

 42 

 46 

 44 

 49 

 52 

 50 



31 

 51 



4 



60 



5 



61 



6 



65 



7 



65 



8.. 



66 



9 



210 





64 



10 6... 





11. 



88 

 77 

 74 

 72 

 74 

 81 

 a 81 

















12 



89 



78 



85 

 80 

 88 

 87 

 94 

 96 

 99 



102 



86 

 75 

 80 

 82 

 83 



96 



107 



114 



120 



a 127 



108 

 103 





253 

 255 



44 

 29 

 21 

 22 

 23 



30 

 39 



38 

 41 



45 



59 



13 



52 



14 





15 



16 



100 





283 

 310 

 332 

 333 

 350 

 365 

 375 



405 



45 

 41 



17 



18 



110 

 110 

 115 

 129 

 135 



290 

 315 

 332 



330 



43 

 43 



19 



85 

 94 

 93 

 99 

 106 



46 



20 



50 



21 



58 



22 





23 





142 



60 



a Estimated. 



b Beginning of dorsal series. 



Sacral vertebrae. — -The description to follow of the sacral vertebrae of Antro- 

 demus is based on the sacra of four individuals, Nos. 4734, 8405, 8423, and 8367, 

 arranged in the order of their importance, but more especially on the splendidly 

 preserved sacrum of No. 4734, U.S.N.M., shown in all aspects in plates 8, 9, and 10. 

 Three of these specimens each have five coosified vertebrae in the complete sacral 

 arcade. As in Tyrannosaurus and Geratosaurus, S t , is directly opposite the pubic 

 peduncle of the articulated ilium (see pi. 9, fig. 2), while S 3 is opposite the ischiac 

 peduncle. It is quite probable that S 2 and S 3 represent the primary sacrals, S x 

 being a modified dorsal, and S 4 and S 5 , modified caudal vertebrae. 



The five sacral centra have concave sides and ventral surfaces, though the 

 flange-like ends of the preceding dorsals are only found on the anterior end of Sj. 

 S 2 and S 3 are much compressed transversely, with the ends little expanded. The 

 lateral depressions on the superior sides of the centra are present in all the sacrals 

 of No. 4732, but in the other individuals these depressions grow shallower from front 

 to the back of the series. 



The ilia are united to the sacrum by stout but exceptionally short sacral ribs 

 and by the transverse processes. There appear to be four distinct sacral ribs (pi. 

 8 sr.). These unite with the sacrals intervertebrally. The anterior rib articu- 

 lates about equally with roughened facets on S 1; S 3 , but the succeeding two are 

 supported more by the posterior centrum — that is, S 3 and S 4 , respectively. The 



