PLATE XVIII. 

 Jurassic Dinosaurs. — Sauropoda. 



ATLA.NTOSAURID.E. 



Page. 



Fig. 1. Cervical vertebra of Apatoaaurus laticoltia Marsh; back view; one- 

 sixteenth natural size 167 



FlG. 2. Dorsal vertebra of Apatosaurus ajax Marsh ; front view ; one-eighth 



natural size 167 



a, metapophysis ; b, ball; c, cup; d, diapophysis ; f, lateral foramen; h, 

 hatchet bone; n, neural canal; p, parapophysis; z, anterior zygapophy- 

 sis; z' , posterior zygapophysis. 

 Fig. 3. Cast of sacral cavity of Apatoaaurus ajax; top view; one-fourth nat- 

 ural size 166 



/, foramen ; i>, cast of cavity in first true sacral vertebra ; v' , cast of cavity 

 in second sacral vertebra; o", cast of cavity in third vertebra. 

 280 





