OSTEOLOGY OF CARNIVOROUS DINOSAURS. 



61 



cover the metacarpal. On the posterior external side a somewhat similar projection 

 overlaps a beveled surface on the outer proximal end of metacarpal II. The outer 

 end of this is separated by a notch from a smaller process on the anterior border 

 that also rests upon a beveled articular facet on the end of 

 metacarpal II. The intermedium has a greatest transverse 

 diameter of 51 mm; greatest antero-posterior diameter is 40 mm. 

 The ulnare is not known. Carpale 2 is apparently repre- 

 sented by the small flattened ossicle that was found attached 

 to the proximal end of metacarpal II (fig. 45 c 2 ) of the right 

 foot, which is in close apposition to the outer anterior border of 

 the intermedium. A detached bone found near the left manus 

 is regarded doubtfully as representing C 3 . It is elongated in 

 one diameter with angularly rounded surface. There is no clew 

 as to the position it occupied on the foot, if indeed it repre- 

 sents such an element. Its longest diameter is 31 mm., with a 

 least diameter of 11 mm. 



Metacarpus. — The complete metacarpus in Anlrodemus 

 apparently consists of three elements, there being no trace 

 in either foot of metacarpal IV, which is present in the manus x 

 of Omiiholestes hermanni Osborn. 



Metacarpal I is a short heavy bone with a deeply grooved 

 distal end that is turned inward away from the central axis 

 of the foot. Resembling Ornithomimus (Strutliiomimus) and 

 Omiiholestes in this respect. The articular facets extend well 

 upward on both front and back aspects (fig. 45, d.), rising about equally above these 

 surfaces of the shaft. The lateral pits are moderately shallow, the outer one being 

 the better defined. Viewed from above, the proximal end is subtriangular in outline 

 with a shallow concave articular end. This surface is opposed in the articulated 



foot by the radiale and intermedium, the former 

 only touching slightly the hinder internal corner, 

 the remaining surface being closely applied to the 

 intermedium, as shown in the right foot, where 

 these bones were found articulated. Metacarpal 

 I articulates closely on its upper half with meta- 

 carpal II (fig. 40), resting in a broad shallow de- 

 pression on the side of that bone. Metacarpal II 

 is an elongate bone, having an expanded sub- 

 quadrangular proximal end, rather a slender, angu- 

 larly rounded shaft, and a less expanded but broad- 

 ly grooved distal extremity. The articular surfaces 

 of the distal end of this bone are continued back- 

 ward in the form of two lateral condylarlike facets, which are separated by a deep 

 and moderately broad notch. The external one is the larger of the two. The inner 

 border of the proximal end is beveled off, forming two facets of unequal size for the 



d 



Fig. 43.— Eight radius or 

 Antrodemus valens 

 Leidy. No. 4734 U.S.N.M. 

 \ nat. size. Internal 



VIEW, d, DISTAL END; p, 

 PROXIMAL END. 



Fig. 44.— Carpal bones of Antrodemds 

 valens Leidt. Cat. No. 4734, U.S.N.M. 

 £ nat. size. Viewed distally. a, radiale 



OF THE RIGHT FORE FOOT; b, INTERMEDIUM 

 OF THE LEFT FORE FOOT; II, SURFACE ARTICU- 

 LATING WITH METACARPAL; I, SURFACE ARTICU- 

 LATING WITH METACARPAL n. 



i Osborn, H. F., Bull. Amer. Nat. Hist., vol. 19, 1903, pp. 462, 463, figs. 2 and 3; also vol. 35, 1917, pp. 735-738, figs. 2-36. 



