Watch List notes:

LESBOS, Mytilene. Circa 521-478 BC. AR Trihemiobol (10mm, 1.45 g). Head of roaring lion right / Quadripartite incuse square. HGC 6, –; CNG 88, lot 326; Münzen und Medaillen GmbH 30, lot 1015; Spink 183, lot 673. Deeply toned. VF. Rare. NOT SUITABLE FOR ENCAPSULATION.

Although unpublished for this denomination, the style on this type is a perfect match, in all respects, to the obverse of a number of the electrum series from Mytilene (cf. Boehringer emissions 12-14).