Watch List notes:

BOEOTIA. Tanagra. 457-448 BC. Tetartemorion (Silver, 5.5 mm, 0.23 g). Boeotian shield. Rev. Τ - Α Horse's head to left; all within incuse square. BCD Boiotia 263 (this coin). V. Demetriadi, Some new fractions from central and southern Greece, pour Denyse, p. 52 and pl. 6, 5 & 5A (but shown with the wrong obverse, this coin). Traité II, 3, 342. Extremely rare, probably the second known. Grey toning. Minor dig on the obverse. Very fine.
From the "Collection sans Pareille" of Ancient Greek Fractions and from the BCD Collection, Triton IX, 10 January 2006, 263.