Green’s Dictionary of Slang

portcullis n.

[the SE portcullis engraved on one side of the silver coin]

a halfpenny.

[UK]Jonson Every Man Out of his Humour III i: It comes well, for I had not so much as the least portcullis of coin before.
[UK]Rowlands Humours Ordinarie C: Then doth he diue into his sloppes profound, Where not a poore port-cullice can be found.