Watch List notes:

The Roman Empire
Gaius, 37 – 41

Denarius, Lugdunum 37-38, AR 3.35 g. C CAESAR AVG GERM P M TR POT COS Bare head of Gaius r. Rev. Radiate head of Augustus r., between two stars. C 11. BMC 4. RIC 2. CBN 3.
Very rare. Two lovely portraits and a light iridescent tone, an insignificant corrosion
on the edge at eleven o'clock on reverse, otherwise about extremely fine

Ex NAC 4, 1991, 314 and Tkalec 17 May 2010, 165 sales. Illustrated on www.romancoins.info, section imagines imperatorum. This specific coin was selected for the upcoming Roman portrait book (see introduction to the auction).
Both portraits of Caligula and Divus Augustus are very interesting. This elegant style is unusual on gold and silver issues of the period. AMP.