A leg. This is as old as Maundeville and Dunbar. (N.E.D.)

1

1781.  See an allusion s.v. BUNDLE.

2

1809.  

        Her arms were as two trapsticks small,
  Her fingers just like thongs;
Her legs,—if legs we might them call,—
  Were like the legs of tongs.
Mass. Spy, July 5.    

3

1854.  She [the Indian maiden] was seated on a large granite rock, her legs (beg pardon—her limbs) stretched as far asunder as convenience permitted.—Knick. Mag., xliii. 554 (June).

4

1858.  [The horse] fell from the stairs which he used to ascend, and, fracturing his limb, his death was rendered necessary.—Pittsburg Chronicle, June (Bartlett).

5

1873.  There are several places where even the thickness of a man’s limb is too much between the horse and the cliff, and he would suffer a fearful squeeze, or be the cause of throwing himself and horse hundreds of feet down the ragged rocks.—J. H. Beadle, ‘The Undeveloped West,’ p. 549 (Phila., &c.).

6