. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. Evolution of Tapiroid Skeleton • Radiusky 91 and superficial layers, respectively, of col- lateral ligaments. The distal ends of the second, fourth, and fifth metacarpals are similar to that of the third, but are trans- xersely compressed and asymmetrical. The fourth metacarpal has approximately the same dimensions as the second. It has a large triangular proximal facet for the unciform and a small lateral facet for the fifth metacarpal. The fifth metacarpal is 58 mm long and 9 mm wide distally, with an elongate, sadd
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. Evolution of Tapiroid Skeleton • Radiusky 91 and superficial layers, respectively, of col- lateral ligaments. The distal ends of the second, fourth, and fifth metacarpals are similar to that of the third, but are trans- xersely compressed and asymmetrical. The fourth metacarpal has approximately the same dimensions as the second. It has a large triangular proximal facet for the unciform and a small lateral facet for the fifth metacarpal. The fifth metacarpal is 58 mm long and 9 mm wide distally, with an elongate, saddle-shaped unciform facet and a narrow medial facet for the fourth meta- carpal. Phalanges: The proximal phalanx of the medial digit is about 21 mm long. Promi- nent raised areas on the posterior face just below the metacarpal facet served for at- tachment of the collateral ligaments; the sesamoidean ligaments probably inserted on the area between them. Tuberosities on left and right sides at the distal end of the posterior face probably mark insertions of parts of the tendo perforatus (superficial digital flexor tendon). On either side of the distal articular facet, a shallow pit sur- mounted by a low tuberosity indicates the attachment area of the collateral ligament and suspensory ligament of the navicular sesamoid. The second phalanx of the third digit is about 13 mm long and 13 mm wide across its proximal end. Low prominences at the proximal end of the posterior face served for insertion of part of the tendo perforatus, and, laterally, the collateral ligaments. Shal- low depressions on each side of tlie distal condyle indicate attachment areas of collat- eral ligaments to the third phalanx. The third, or ungual, phalanx of the me- dian digit measures about 20 mm long and has a maximum width of 16 mm. The me- dial fissure is \'ery short. A large raised area on the proximal end of the posterior surface marks the insertion of the tendo perforans (deep digital flexor tendon).
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Keywords: ., bookauthorharvarduniversity, bookcentury1900, booksubjectzoology
