456 Annals of the Carnegie Museum. 



as in the latter it is saddle-shaped, convex antero-posteriorly and con- 

 cave laterally. The pisiform articulation on the shaft is almost con- 

 tinuous with the cuneiform facet and is placed as high as the upper 

 margin of the posterior scaphoid facet. The inner angle of the radius 

 is as well developed in O. lougipes as in the llama. 



The Scaphoid. — The scaphoid (No. 886) is proportionally smaller 

 than in the llama, but resembles it in its general characters. In the 

 cotype this bone is narrow transversely and deep antero-posteriorly. 

 The anterior part of the proximal articulation is a broad convex ridge, 

 and the posterior part is concave and terminates in an elevated, sharp, 

 hook-like border. The inner side is rounded and rugose, the external 

 ulnar surface is a vertical plane with three distinct facets for the lunar, 

 which are as well developed as those of the llama, the anterior facet 

 near the distal end being the smallest of the three. Between the last 

 mentioned facet and the posterior rounded facet, there is a deep tri- 

 angular pit, with its broad exit directed downward. Distally the 

 scaphoid has two facets, for the trapezoid and the magnum. The 

 first mentioned is a rounded concavity on the postero-radial part of 

 the bone and the magnum facet is flat and occupies the entire an- 

 terior face. 



The Lunar. — The lunar (No. 886) is proportionately greater in size 

 than is that of the llama and the camel. The wedge or beak extends 

 below both scaphoid and cuneiform when in position in the carpus. 

 The bone is as broad as the scaphoid and higher. Its antero-pos- 

 terior diameter is nearly as great as that of the scaphoid. This is 

 chiefly due to the long, heavy, posterior arm, which greatly exceeds 

 that of the llama in size. The proximal articulation is irregularly 

 convex fore and aft and somewhat triangular in shape. The radial 

 side has three facets corresponding to those of the scaphoid with 

 which it articulates. On the radial and ulnar sides the lunar is deeply 

 excavated and the bone has an elongated vertical appearance, especi- 

 ally when seen from in front. 



There are two posterior processes, the shorter projects outwards 

 and downwards on the ulnar side, abutting against the cuneiform and 

 unciform, the longer process extends posteriorly, slightly radially and 

 has a beak-like decurved tubercle which forms the apex of the facet 

 for the magnum. Distally the unciform and magnum facet are equal 

 in size and meet nearly at right angles, thus forming a wedge-shaped 

 beak, which is longer than is that in the llama and the camel. 



