The Sextans denomination
The sextans was an Ancient Roman bronze coin produced during the Roman Republic valued at one-sixth of an as (2 unciae).

The most common design for the sextans was the bust of Mercury and two pellets (indicating two unciae) on the obverse and the prow of a galley on the reverse.

Earlier types depicted a scallop shell, a caduceus, or other symbols on the obverse.
Sextans

(1) Caelia 220-150 BC
Obverse: Head of Athena right wearing crested helmet; ●●
Reverse: Trophy of captured arms, helmet spear, palm branch and shield decoraded with Medusa head; club left; KAIΛIN_ΩN
Ref: HNItaly 762; Weber 439; SNG ANS 670...
AE Sextans Sardinia
Obverse: draped bust of Mercury right wearing winged petasos; ●●
Reverse: prow of galley right, fighting platform with club; ROMA / C /●●
Ref: Crawford 63/6, Sydenham 157d, BMCRR...
(3) Rome | Anonymous 211-208 BC
Obverse: draped bust of Mercury right wearing winged petasos ●●
Reverse: prow of galley right, fighting platform with club ROMA ●●
Ref: Crawford 056/06, McCabe F1.Sx.2 Luc...
(4) Rome | Anonymous 211-210 BC
Obverse: draped bust of Mercury right wearing winged petasos ●●
Reverse: prow of galley right, fighting platform with club; grain ear above ROMA ●●
Ref: Crawford 72/8; Sydenham 195d; RBW 3...
(5) Rome | Anonymous 206-190 BC
Obverse: draped bust of Mercury right wearing winged petasos, ●●
Reverse: prow of galley right; ROMA / ●●
Ref: Crawford 056/06, McCabe J1.Sx.1
(6) Rome | Anonymous 211-208 BC
Obverse: draped bust of Mercury right wearing winged petasos; ●●
Reverse: prow of galley with corvus right, grain ear above; I< / ROMA
Ref: Crawford 069/06b; RBW 294