Agathokles, Syracuse, Sicily. Electrum 100 litrae. ca. 317-289 BC. 19mm, 6.70 g. 

SYRAKOSIWN, laureate head of Apollo left, lunar eclipse  behind head.
SWTEIRA, diademed head of Artemis right, quiver and crescent  behind head.

Jenkins group Daa (this coin).

With permission of Nomos AG obolos 5, lot 72, June 2016.
Of the highest rarity, one of possibly only two known.

Ex James et Sneja Velkov collection, Vinchon, Nov. 1994; 
Monnaies et Médailles auction 37, lot 141 (Dec. 1968); ex 
Ars Classica IV (1922), X (1925) and XVI (1933).

The Jenkins reference refers to his article "Electrum Coinage at Syracuse" in "Essays in Greek coinage, presented to Stanley Robinson".