. Bulletin - United States National Museum. Science. OSTEOLOGY OF CARNIVOROUS DINOSAURS. 75 by smooth but vertically concave ends. With the exception of the joint between the first and second phalanx of digit III, all of the other joints in the pes are keeled. Those of the median or third digit are broad and illy defined, but the remaining artic- ulations have a pronounced median keel on the proximal ends and a corresponding median vertical depression on the distal ends, thus forming strong joints that would be difficult of lateral dislocation. Deep lateral pits are present on both sides in al
. Bulletin - United States National Museum. Science. OSTEOLOGY OF CARNIVOROUS DINOSAURS. 75 by smooth but vertically concave ends. With the exception of the joint between the first and second phalanx of digit III, all of the other joints in the pes are keeled. Those of the median or third digit are broad and illy defined, but the remaining artic- ulations have a pronounced median keel on the proximal ends and a corresponding median vertical depression on the distal ends, thus forming strong joints that would be difficult of lateral dislocation. Deep lateral pits are present on both sides in all of the phalanges. The ter- minal plialanges are moderately curved bones, sharply pointed in front, deeply grooved on the side for the external claw, which in life would have con- siderably increased the size of these appendages. The unguals of digits II and III are about subequal in size, while those of digits I and IV are considerably reduced. The ungual phalanges of the pes are readily distinguished from those of the manus, by the greater curvature of the latter, and the inferior development of the bone below the articulating surface for the preceding phalanx, also those of the manus are more compressed trans- versely. The shape of these clawed unguals, appear to indicate that these feet were better adapted for locomotion . , t ^r . 'â Fig. 52.âLeft hind foot of Antrodemvs Leidt. No. than lor grasping purposes. 4734, restored, j size, (after m.^rsh.). Measurements of left hind feet of Antrodemus valens Leidy.' DIGITS. No. 4734, No. S123, 11. III. IV. I. II. III. IV. Greatest length'of metatarsals. mm. 85 mm. 270 60 72 42 mm. 327 64 80 40 mm. 275 90 65 36 mm. mm. 320 mm. 353 67 80 38 mm. 324 67 76 45 92 Greatest transverse diameter/distal end 38 57 36 PHALANGIALS. Greatest length: Proximal row 70 270 120 80 110 = 90 66 75 50 30 29 122 116 94 74 72 Fif th'row = 75 â First digit measurements are from the right foot. 2
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