Watch List notes:

ARKADIA, Arkadian League. Tegea. Circa 465-460 BC. Hemidrachm (Silver, 15 mm, 2.98 g, 8 h). Zeus Lykaios, seen partially from behind, seated left on low throne with swan's head on the backrest, holding long scepter in his left hand and with eagle flying left over his right. Rev. [APKADIKΟΝ], some letters legible Head of Kallisto facing, wearing hair band, earrings and a necklace, and with her hair in tight curls over her forehead, tied in a long plait at the back and then turned so that the bun is visible to her left. BCD -. Williams 178 (O.122/R.110). Extremely rare. Toned and with a most unusual facing head of a rather Archaic style. Reverse surfaces somewhat rough, otherwise, nearly extremely fine.
From a British collection, ex Roma E-Sale 8, 31 May 2014, 112.

This extraordinary head can be almost exactly paralleled by that on a terracotta statuette of a woman, dated to c. 450 BC and of marginally later style than this piece: once in the Erlenmeyer collection it is now in a private collection (see http://www.cb-gallery.com/en/produkt/attische-kore/). Another very similar terracotta is now in the British Museum, 1926.1115.4 (acquired in 1926 and apparently found in Boeotia in the area of Lake Copais: https://www.britishmuseum.org/research/collection_online/collection_object_details.aspx?objectId=461814&partId=1&matcult=16099&page=1).