Watch List notes:

Sex. Atilius Saranus/Serranus. 155 B.C. AE quadrans (22.04 mm, 8.02 g, 11 h). Rome mint. Laureate head of Saturn right; S behind / SAR, prow of galley right; S to right, ROMA below. Crawford 199/5; Sydenham 378c; BMCRR 754. aEF, flat strike. Very Rare. 

Ex RBW collection (not in previous sales); Ex Spink & Son 9/86.