Watch List notes:

Sex. Atilius Saranus/Serranus. 155 B.C. AE semis (29.5 mm, 16.02 g, 7 h). Rome mint. Laureate head of Saturn right; S behind / SAR, prow of galley right; S to right, ROMA below. Crawford 199/3; Sydenham 378a. Fine. Very Rare. 

Ex RBW collection (not in previous sales); Ex Peus auction 330, lot 646.