4^4 SMITHSONIAN MISCELLANEOUS COLLECTIONS [vOL. 45 



small, rudimentary centra, longer than wide and without processes 

 of any kind. 



Stcniuni and Ribs (pis. xcv, i; xciv, 7). — The structure of the 

 sternum of Bracliylagiis is fairly characteristic of the genus. The pre- 

 sternum is compressed, bearing a low keel along the whole ventral 

 border. The dorsal portion of the presternum is somewhat enlarged 

 laterally just anterior to the attachment of the first pair of ribs, which 

 takes place at the junction of the anterior and middle thirds. The 

 mesosternum consists of four distinct segments, of which the first is 

 compressed laterally, with a low keel continuing that of the prester- 

 num. The succeeding mesosternal segments become successively 

 wider, and more flattened dorso-ventrally. The last segment is much 

 wider than any of the others, with well marked postero-lateral angles, 

 for the attachment of the sixth and seventh pairs of ribs. The xiphi- 

 sternum is decidedly longer than the presternum, is slender in the 

 middle but considerably expanded at the ends, especially the pos- 

 terior one. 



The ribs are not very characteristic in BracJiylagiis. In general 

 they resemble those of Syh'ilagiis. The spine-like portion of the 

 tubercles are but moderately developed and are last seen on the 

 seventh pair of ribs. The lower part of the shafts of the anterior 

 ribs is but slightly broadened. 



Shoulder Girdle and Upper Extremity. — There is apparently noth- 

 ing about the shoulder blade (pi. xcvii, 8) of Brachylagits except the 

 smaller size by which to distinguish it from the scapulae of several 

 other genera. It belongs to the moderately narrow type with a 

 relatively straighter and less convex vertebral border, with the 

 antero-superior angle of the more pronounced type, and the supra- 

 spinous fossa relatively narrower. 



There is little in the humerus of Bracliylagiis that is peculiar. It 

 is small and relatively more slender than in other genera except 

 Romcrolagus. The groove subtending the internal condyle is 

 moderately developed. The external condyloid ridge is rather wide 

 for one of the Leporidae, like that of Romcrolagus, but not quite so 

 long. 



In Brachylagus the radius and ulna (pi. xcviii, 6) are subecjual 

 in size, and in general resemble those bones in Syh'ilagus, Orycto- 

 lagus, Pronolagus, and Limnolagus. Unlike any of those skeletons, 

 however, with bones of the foramen equally developed, the radius is 

 distinctly shorter than the humerus, in the other cases the humerus 

 and radius are subequal in length. 



The carpal bones, the metacarpals, and the phalanges of Brachy- 



