PLATE XXI. 



Ichthyosaurus. 



Typical vertebrae. 

 Fig. 



1. First or atlas vertebra. 



2. Trunk-vertebra. 



3. Pelvic vertebra. 



4. Caudal vertebra. 



5. Terminal or pinnigerous vertebra. 



(These figures are less than the natural size.) 



6. Neural arches of trunk-vertebras, side view. 



7. Portions of pleurapophyses of trunk-vertebras, outer side view. 



(These figures are of a small specimen, natural size.) 



