41 8 DINOSAURIA 



Order I. SAUROPODA. 



Pubes simple, with symphysis. Premaxillae with teeth. 

 Plantigrade. 



The teeth are mostly spatulate, laterally compressed, with 

 sharp edges, but without serrations. Skull with a pair of large 

 pre-orbital fossae. The centra of the vertebrae of the trunk have 

 large lateral cavities. The fore- and hind-limbs are pentadactyle, 

 plantigrade, and hoofed, of the typical walking type ; the bones 

 of the limbs are stout and solid ; the femur is devoid of an inner 

 distal or fourth trochanter. The carpal and tarsal bones are free. 

 Herbivorous. The Sauropoda comprise some of the most gigantic 

 terrestrial creatures which have ever existed, compared with some of 

 which the bulk of an elephant appears almost insignificant. Their 



FIG. 95. Skeleton of Brontosaurus excelsus. x T ^ f> . (After Marsh.) 



range in time extends from the Lower Oolite into the Cretaceous, 

 with a perhaps world-wide distribution, namely, Western Europe, 

 North America, Patagonia, Madagascar, and India. Although 

 they are, except for their size, the least specialised of all 

 Dinosaurs, none of the Sauropoda hitherto discovered are old 

 enough to claim to be the ancestors of the other Dinosaurs. 



Brontosaurus excelsus of the Upper Jurassic of Wyoming was 

 a giant at least 6 feet long and about 1 feet high. The head 

 is extremely small in proportion, not so broad as the fourth of 

 the thirteen vertebrae of the long and flexible neck. The 

 trunk is comparatively short, the tail longer than the neck, and 

 provided with numerous chevron-bones. Most of the vertebrae 

 are hollow, especially the five co-ossified sacrals. The spinal canal 

 of the sacral region is very wide, indicating a strong sacral 

 swelling in conformity with the huge posterior limbs. The 

 pubic bones are stronger than the ischia. The long axis of the 



