JURASSIC VERTEBRATE FOSSILS. 



493 



likewise near Canyon, in the saint' horizon. The great perfection of 

 the remains of this genus from the western localities has enabled the writer 

 to make a careful study of the whole skeleton, and thus determine many 

 important points in the anatomy of the Sauropoda hitherto unknown. In 

 fig. 39, opposite, a tooth of Brontosaurus is represented, and this may be 

 regarded as typical of the Sauropoda in general. A cervical vertebra of 

 the same species is shown in figs. 40 and 41. and this indicates the dedicate. 



Fig. 42.— Dorsal vertebra of Brontosaurus excelms; aide view. One-twelfth natural Bize. 

 Fig. 43.— Fourth caudal vertebra <>i Brontosaurus exeelsus; side view. One-eightb natural size. 

 &, ball j c, cup; c', face for chevron ; d, diapophysis; /, foramen in centrum; p, parapophysis ; s, neural spine; 

 r. anterior zygapophysis; s . posterior zygapopbysis. 



bird-Hke neck of this huge reptile. In fig. 42 a dorsal vertebra of the same 

 individual is represented, which also shows how the trunk vertebras were 

 lightened in a corresponding manner. The sacrum in this genus was quite 

 hollow, and was composed of five coalesced vertebras. The anterior caudal 

 vertebrae, and even the ribs, wen- more or less lightened l>v cavities, hut 

 the rest of the caudal vertebrae and all of the limb bones were quite solid. 



