10 



PROCEEDINGS OF THE NATIONAL MUSEUM 



VOL. 87 



I 



tarsal III when articulated. Below this beveled articular surface 

 there is a slight divarication of the distal end outward from the axis 

 of the foot. The proximal end is somewhat damaged 'through crush- 

 ing, so that its precise form cannot be determined from this specimen. 

 The distal face is quadrangular, the articular surface rounding well 

 up on the anterior face and broadly hollowed out on the posterior 

 side. The outer lateral face is slightly hollowed 

 out. 



Metatarsal III is the longest bone of the pes. 

 Viewed from the front the distal end is widest, 

 gradually narrowing to the proximal end where 

 the greatest diameter is anteroposterior. The inner 

 side presents a beveled surface that looks forward 

 and inward for the articulation of metatarsal II. 

 The outer border is flattened on the upper third 

 for the articulation of metatarsal IV. 



Metatarsal IV is widely expanded at the prox- 

 imal end. The proximal articular face is subtri- 

 angular in outline, with a cupped surface. The 

 shaft is flattened anteroposteriorly, with the outer 

 border presenting a sharp edge. The inner side 

 shows a hollowed-out proximal surface that be- 

 comes flattened ventrally and disappears below 

 the middle of the bone. This flattened surface 

 indicates the contact between metatarsal III and 

 IV. Below this contact the bone is divaricated 

 outward away from the axis of the foot. 



The distal end has the greatest diameter antero- 

 posteriorly, and the outer side of the distal end 

 is hollowed out with a strong lip given off from 

 the posterior border. 



No trace was found of a vestigial meta- 

 tarsal V. 



The phalangial formula is the typical 2, 3, 4, 

 5, 0, and all but the ungual of digit I are present. 

 FIGURE 9.— Ischium of The euds of both the metatarsals and the pha- 



Leptoceratops sp. -, j. ii j.- i j: J.^ 



(USNM. No. 13864) : I^-Uges present smooth articular surfaces, thus 

 Lateral view. One- indicating it to be a strong, compact, well-articu- 



half natural size. ^^^^^ ^^^^ 



The proximal phalanges have puUy-shaped distal and concave 

 proximal ends. A median, rounded, vertical ridge on the proximal 

 end fits into a corresponding depression on the distal end of another, 

 thus forming a strong union of the phalanges, which permits but 

 little lateral motion. There are moderately deep, well-defined pits 



