43^ SMITHSONIAN MISCELLANEOUS COLLECTIONS [vOL. -15 



last seven, or about that number, have no ventral attachments, while 

 the intermediate three pairs are attached to the costal cartilages of the 

 ribs in front. The ribs are all slender and weak compared with the 

 ribs of the Leporidas, and none of them possesses well-developed 

 spine-like tubercles, but between the heads and tubercles the anterior 

 ribs are rather broad and heavy. 



Shoulder Girdle and Upper Extremity. — In Oehotona, the clavicle 

 (pi. xcvi, 2) is well developed; its outer end is enlarged, flattened, 

 and connected by a ligament to the greater tuberosity of the humerus. 

 The inner end articulates directly with the extreme anterior portion of 

 the presternum. 



The scapula (pi. xc\n, 5) has the general outline of a right- 

 angled triangle with the right angle very much rounded off. The 

 acromion process is very long and slender and about three times th.^ 

 length of the actual scapular spine. The metacromion is well de- 

 veloped. The posterior border of the scapula is long and concave; 

 the superior border is relatively long and much rounded, so that it 

 gradually passes into the anterior border. The distance between the 

 antero-superior and postero-superior angles is contained a little more 

 than once in the length of the scapifla, taken along the attachment 

 of the spine. 



The humerus of Oehotona is in general very much like the sam.e 

 bone in Lepiis and its allies. The head of the bone is rather more 

 globular, and the bicipital groove does not encroach on its anterior 

 surface. The anterior tuberosity does not project above the head of 

 the bone, so that the latter point is its highest part. When viewed 

 from the side, the head of the humerus is seen to project rather 

 backward, so as to form a sort of hook with the shaft of the bone. 

 The double trochlear surface, at the distal end of the bone, is rather 

 wide and shallow. The groove subtending the internal condyle is 

 poorly developed. 



The bones of the forearm (pi. xcviii, 11) in Oehotona are 

 similar to the forearm bones of Pentalagus (page 430). The ulna is 

 distinctly larger than the radius throughout its wdiole extent. The 

 outer portion of the distal extremity of the ulna is prolonged down- 

 ward into a convex articular surface which fits into a corresponding 

 concavity formed by the cuneiform and pisiform bones. There is 

 also a concave facet just internal to this projection which articulates 

 with a corresponding convexity on the cuneiform. 



The structure of the carpus of Oehotona is best understood by an 

 examination of the figures (page 379). Compared with the carpus of 

 Lepiis and its allies the dorso-palmar depth of the pisiform is 



