Watch List notes:

The Roman Empire
Gaius, 37 – 41

Sestertius 37-38, Æ 30.89 g. C CAESAR AVG GERMANICVS PON M TR POT Bare head l. Rev. S P Q R / P P / OB CIVES / SERVATOS within wreath. C 24. BMC 38. RIC 37. CBN 50.
A magnificent portrait of fine style and a pleasant brown-green patina
somewhat tooled, otherwise good extremely fine

Illustrated on www.romancoins.info, section imagines imperatorum. This coin will be included in the upcoming book on portraits on Roman coins (see introduction to this auction catalogue).
In my view this is one of the best styles of portrait of Caligula on coins. Caligula presents himself as monarch, against the will of the Roman aristocracy. AMP.