Fig. 19 in Skeletal Adaptations of Ornitholestes, Struthiomimus, Tyrannosaurus

Fig. 19. Sacro-pelvic arcade of Tyrannosaurus rex of the genotype specimen Amer. Mus. 973, discovered in Hell Creek, Montana, in 1904. A, Sacral aspect of the right ilium showing the respective attachments of the five sacrals S 1-5. B, Left lateral aspect of the sacrum, exhibiting centra of S 1-5, also the sacral rib attachments S 1-5 to the inner aspect of the left ilium. C, Anterior aspect of the sacro-iliac arcade, SI, the first sacral vertebra. D, Posterior aspect of the sacro-iliac arcade showing S5, the fifth sacral. All figures one fifteenth natural size.