AVilliston.] Mosasaurs. 221 



PL/ATE LX. — Fig. 1, right quadrate of Tylosaurus proriger, from behind; 

 fig. 2, left quadrate of same, from within ; fig. 3, left quadrate of Plate- 

 carpus coryphaeus, from without; fig. 4, right quadrate of Clidastes 

 icestii, from in front ; fig. 5, right quadrate of Clidastes tortor, from 

 without : fig. 6, right quadrate of Clidastes velox, from behind ; fig. 7, 

 left quadrate of same, from within. 



PLATE LXI. — Figs. 1, 2, quadrates of Tylosaurus dyspelor, from without and 

 within ; fig. 3, right scapula of Platecarpus coryphaeus, from without ; 

 fig. 1, left quadrate of Clidastes tortor, from within. 



PLATE LXII. — Fig. 1, humerus of Brachysaurus overtonii; fig. 2, coracoid 

 of same ; fig. 3, skeleton of Clidastes velox, in matrix. 



PLATE LXIII. — Platecarpus coryphaeus : fig. 1, parietal bone, from below; 

 fig. 2, petrosals, from behind ; fig. 3, left jugal, from within ; fig. 4, left 

 prosquamosal, from within; fig. 5, odontoid; fig. 6, atlantar intercentrum ; 

 figs. 7, 8, lateral pieces of atlas, from within and without ; fig. 9, coronoid ; 

 fig. 10, surangular, from within; fig. 11, articulo-angular, from within. 



PLATE LXIV.— Fig. 1, left quadrate of Clidastes tortor, from behind ; fig. 2, 

 left quadrate of Platecarpus coryphaus, from without; anterior caudal 

 vertebra? of Platecarpus coryjihceus, in matrix; quadrates of same. 



PLATE LXW — Posterior thoracic and anterior dorsolumbal vertebrae and ribs 

 of Tylosaurus proriger, in matrix. 



PLATE LXVI. — Posterior caudal vertebrae of Tylosaurus proriger, in matrix. 



PLATE LXVII. — Terminal caudal vertebrae of Tylosaurus proriger, in mat- 

 rix, continuation of those in plate LXVI, the proximal ones showing 

 ante-mortem injuries. 



PLATE LXVIII. — Slab with specimen of Tylosaurus proriger, on which im- 

 prints of skin occur; the impressions are at the left side below the verte- 

 brae and ribs. 



PLATE LXIX.— -Skin impression of Tylosaurus proriger. 



PLATE LXX.— Photographic reproduction of part of plate LXIX, reversed. 



PLATE LXXI. — Restoration of Clidastes velox, as in life, the middle figure; 

 restoration of Uintacrinus socialis at left; restoration of Ornithostoma 

 ingens at right. 



PLATE LXXII. — Restoration of the skeletons of Kansas Mosasaurs: fig. 1, 

 CUdastes velox; fig. 2, Platecarpus coryphaeus; fig. 3, Tylosaurus 

 proriger. 



