Watch List notes:

SICILY, Akragas (Agrigentum), (c.500-480 B.C.), silver didrachm, Jenkins Group IV, (8.61 g), obv. eagle with closed wings standing to right, A.A before, KR ibehind reversed, rev. crab within circular incuse field, below male head right, (S.709A, cf.Jenkins Pl.37, 9, HGC 2 99, SNG Cop.29 [Pl.1]. SNG ANS 959 [same dies], Boston 229). Good silver with dark grey patina, off centred on the reverse, otherwise very fine/good very fine and a very rare variety.

Ex George Mihailuk Collection, from Harry Larkin in the 1960s.
This issue is very rare with the ethnic arranged this way on the obverse, a similar example in Gemini Auction II (lot 18) 11 January 2006 realised $2200 US.