EXPLANATION OF PLATE XXXVII. 



Quadrate bones of seventeen species of Pytlwnomoipha. From figs- 1 to 11, one-half natural size; figs. 

 12 to 17, one-third natural size. In all, fig. a represents tbe external side ; fig. b, tbepostero-interual, 

 or internal vieve ; fig. e, tbe proximal ; and, fig. d, tbe distal articular faces. Iu figs. 5, 10, and 13, 

 tbe angles and ridges are indicated as follows : a is tbe "knob," or tbe ridge homologous -with it ; 

 /}, median posterior ridge ; y, tbe distal internal longitudinal ; i\ tbe internal longitudinal, or simply 

 tbe internal ridge; e, tbe proximal internal angle ; J, tbe alar process. 



Fig. 1. Clidastcs propytlwn. 



2. Clidastcs tortor. 



3. Clidastes stenops. 



4. Liodon validus. In fig. c, tbe internal angle of tbe proximal articular face is turned to tbe left 



It should be turned to tbe right, in order to correspond with figs, a aud b, and those of t'»e. 

 other species. Moreover, tbe posterior book and alar process are broken away. 



5. Liodon dyspclor. 



6. Liodon prorigcr, flattened by pressure. 



7. Platecarpus mudgei. 



8. Platecarpus ictericus. 



9. Platecarpus coryphwus. 



10. Platecarpus curtiroslris. 



11. Platecarpus tywpaniticus. 

 Vi. Mosasaurus deprcssus. 



13. Mosasaurus fulciatus. 



14. Mosasaurus giganteus. 



15. Uosasaurus maximus. 

 1G. Uosasaurus dcl'ayi. 

 17. Mosasaurus oarlhrus. 



