EXPLANATION OF PLATE XXXVIL 



Quadrate bones of seventeen species of Pi/thonomorjjha. From fi^s. 1 to 11, one-hiilf natural size ; figs. 

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

 or internal view ; fig. c, the proximal ; and, fig. d, tbe distal articular faces. In figs. 5, 10, and K!, 

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

 ji, median posterior ridge ; y, the distal internal longitudinal ; (5, the internal longitudinal, or simply 

 the internal ridge; e, the proximal internal angle ; C, the alar process. 



Tig. 1. CUdastes in-opython. 



2. CUdasles tortor. 



3. CUdastes stenops. 



4. Liodon ralidus. In fig. c, tbe internal angle of the prosiuial articular face is turned to the left 



It should be turned to the right, in order to correspond with figs, a and fc, and those of tHe. 

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



5. Liodon di/spelor. 



G. Liodon prmiger, flattened by pressure. 

 1 .' Platecarpus mudgci. 



8. Platecarpus ictericus. 



9. Plalecarpua comjpJiceua, 



10. Platecarpus curlirostria. 



11. Platecarpus tympanUicus. 

 \'l. Mosasaiirus dcpreasus. 

 K^. Mosasaurus fuJciatus. 



14. Mosasaurus gigantcua. 

 Ui. Mosasaurus maximus. 

 IG. Mosasaurus dcJcayi. 

 17. Mosasaurus oarihrut. 



