Williston.] Mosasaurs. 219 



PLATE XXXIV. — Pelvis and part of left hind paddle of Clldastes velox : II, 

 ilium : P, pubis : Is, ischium ; F, femur : T, tibia ; Fi, fibula ; Ta, tar- 

 sal Imc, first metatarsal. Three-fourths natural size. 



PLATE XXXV. — Pectoral girdle and part of right front paddle of Clidastes 

 westii: S, scapula ; C, coracoid ; H, humerus; E, radius: U, ulna ; I, 

 77, and IV, first, second and fourth metacarpals. 



PLATE XXXVI. — Part of right hind paddle of Clidastes tvestii: femur, tibia, 

 fibula, tarsals, and first metatarsal. 



PLATE XXXVII. — Right scapula and coracoid of Clidastes tortor, from with- 

 out : S, scapula ; C, coracoid. 



PLATE XXX VIII.— Part of left front paddle of Clidastes tortor: h, hu- 

 merus : r, radius ; u, ulna ; tie, ulnare ; re, radiale ; o, third carpal of distal 

 row ; Imc, first metacarpal. 



PLATE XXXIX. — Upper two figures: proximal and distal ends of humerus of 

 Clidastes westii ; right-hand figure, right pelvic bones of Clidastes tor- 

 tor, the upper element the ilium, the lower right one the pubis, the lower 

 left one the ischium: lower left-hand figure, the left pelvic bones of Cli- 

 dastes dispar Marsh, after Marsh. 



PLATE XL. — Tylosaurus proriger. Fig. 1, femur, from below; fig. 2, ilium; 

 fig. 3, right ischium, from without; fig. 4, left ischium, from within; fig. 5, 

 femur, from above; fig. 6, radius; fig. 7, metacarpal; fig. 8, ulna; fig. 9, 

 radius: figs. 10 and 11, indeterminate bones of Brachysaurus overtonii. 



PLATE XLI. — Fig. la, left ilium "of Tylosaurus proriger, from without: lb, 

 pubis of same; lc, ischium of same; fig. 2, pubis of Platecarpus; fig. 2a, 

 ischium of same; fig. 3, posterior cervical vertebra of Baptosaurus on- 

 chognathus, from behind, after Dollo; fig. 4, posterior cervical vertebra 

 of T. dyspelor, from behind ; fig. 5, the same, from the side. 



PLATE XLII. — Fig. 1, Pygal vertebra of Tylosaurus dyspelor, from behind; 

 fig. 2, the same, of another specimen, from in front; figs. 3, 4, median 

 dorsal vertebra of Platecarpus coryphceus, from the side and from be- 

 hind; figs. 5, 6, posterior cervical vertebra of Clidastes tortor, from be- 

 hind and from the side. 



PLATE XLIII. — Platecarpus ictericus: S, scapula, from without; C, right 

 coracoid, from without. 



PLATE XLIV. — Right front paddle of Platecarpus ictericus, from above, after 

 a drawing made in situ by the author : H, humerus ; R, radius ; U, ulna ; 

 MC, metacarpals ; /and 77", III, IV, V, first to fifth digits. 



PLATE XLV. — Fig. 1, radius of Platecar%)us, side and end views ; fig. 2, tibia 

 1 ?) of Platecarpus, side and end views ; fig. 3, humerus of ? Platecarpus 

 crassarfiis, after Cope ; fig. 5, dorsal vertebra of same, from below ; fig. 4, 

 indeterminate paddle bone of same. 



