Watch List notes:

GREEK COINS
EGYPT

Arsinoe III, wife of Ptolemy IV (221-204) and queen of Egypt, 220-204. Octodrachm (Gold, 27mm, 27.77 g 12), Alexandria. Bust of Arsinoe III to right (in the style of Arsinoe II), veiled, wearing stephane and ram's horn, and with a lotos-tipped scepter behind; in field to left, Λ. Rev. ΑΡΣΙΝΟΗΣ ΦΙΛΑΔΕΛΦΟΥ Double cornucopiae filled with fruits and bound with fillet. BMFA 2286. Svoronos 1165. Very rare and with an intriguing portrait. Some minor edge marks and scratches, otherwise, extremely fine.

From the Chrysos Collection, acquired in Geneva in 1980, ex Monnaies et Médailles 52, 19 June 1975, 242, Bank Leu 7, 9 May 1973, 305 and Hess-Leu [3], 27 March 1956, 336.
The portrait on the obverse of this coin, while clearly based on that of Arsinoe II, is surely that of a younger woman: in this case, Arsinoe III.