THE HIND LIMB AND FOOT 63 



on the flattened external face of the bone. The distal end is expanded, with the outer aspect concave 

 in the vertical plane. The articular face is quadrangular and turned to look somewhat outward as 



though the digit divaricated away from the axis of the foot. The first digit could not have borne 

 much if any weight. Metatarsal 1 1 is a little longer than IV. The proximal end is elongated antero- 

 posteriorly, the lateral sides flattened and parallel, and the posterior somewhat rounded, with a 

 slightly rugose area opposing that of metatarsal I. The proximal facet is slightly concave as in 1. 

 The distal end is dilated, with the distal facet convex antero-posteriorly. The shaft is fairly straight, 

 but tapering fore and aft. 



Metatarsal III, evidently the axial one, is the longest. The proximal end is flattened on the 

 inner side, rounded more or less externally except where it makes contact with metatarsal IV. The 

 shaft is slightly curved, with the concave side outermost. The shaft is thickest antero-posteriorly at 

 the proximal end and widens somewhat transversely distally but not as much as in C. nasicomus. 

 The bone is somewhat rugose on the proximal half of the inner face. 



Metatarsal IV is broadly expanded proximally, and has a flattened shaft, with a distinct keel 

 on the outer face of the distal half. The rear of the shaft is concave, the front only slightly so. 

 There is a triangular, flattened area on the interior aspect for contact with the third metatarsal, 

 which is half as long again. 



Metatarsal V is vestigial and about two-thirds the length of metatarsal I. The proximal end is 

 comparatively large and ovate and the shaft laterally compressed, the antero-posterior diameter being 

 three or four times as great as the transverse. The distal end is small and rounded, without trace of 

 articular facet. This bone bore no phalanges and served no other function than to increase the 

 lateral diameter of the metatarsus and thus to aid indirectly in supporting the creature's weight. 



The phalanges exhibit nothing unusual. The proximal one of digit I is nearly twice as long as 

 wide, but all of the others are wider than long, except the unguals, which are depressed, spade-like 

 bones. The general pose of both manus and pes is digitigrade. The circumference of the restored 

 foot, with the sole pad, is about 1360 mm., that of the hand is 1090 mm., which makes the plantar 

 area of the pes roughly nearly twice that of the manus and presumably gives an approximation of 

 the relative weight borne by each. 



Dimensions of Pes 



C. nasicomus C. cutleri C. flexus Y.P.M. 



Length of metatarsal 1 123 mm. 



Length of metatarsal II 180 



Length of metatarsal III 215 



Length of metatarsal IV 160 



Length of metatarsal V 77 



Length of phalanx 1-1 101 



Length of phalanx 1-2 97 



Length of phalanx II-l 69 



Length of phalanx II-2 46 



Length of phalanx II-3 93 



Length of phalanx III-l 60 



Length of phalanx III-2 37 



Length of phalanx III-3 35 



Length of phalanx III-4 80 



Length of phalanx IV-1 54 



Length of phalanx IV-2 35 



Length of phalanx IV-3 32 



Length of phalanx IV-4 23 



Length of phalanx IV-5 69 



87 Artificial. 



88 Is it not more probable that this is III-4? It would seem so from the photograph. 



