The Tetras denomination
The Tetras was a bronze denomination within the Sicilian Greek system corresponding to 4 onkia - or one third of a Litra.

The tetras was denoted by four pellets on the reverse.
Tetras
(1) Agyrion
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An AE Tetras struck 339/338-317 BC in Agyrion
Obverse: crude head of Ares or Athena right wearing crested Attic helmet

Reverse: club; AΓYPI / NAIΩN

Diameter: 19.5 mm
Die Orientation: -
Weight: 6.9 g
No notes for this coin
Campana 11; CNS III, 20 OS; SNG ANS -; HGC 2, 54
(2) Akragas
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An AE Tetras struck 425-406 BC in Akragas
Obverse: eagle right, tearing at hare AKP_A

Reverse: Crab, crayfish left below •••

Diameter: 21 mm
Die Orientation: -
Weight: 9.21 g
No notes for this coin
SNG COP. 75 var. SNG München 132
(3) Solus
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An AE Tetras struck c. 400-300 BC in Solus
Obverse: head of Athena half left wearing Corinthian helmet

Reverse: warrior kneeling right, drawing bow, shooting arrow; KPRA (kapara meaning village)

Diameter: 15 mm
Die Orientation: -
Weight: 2.3 g
No notes for this coin
cf. Calciati I pg. 310, 5 (same); SNG ANS 743.