There's probably a something-second coin called a Mo, because Humans Are Just Like That (tm). Plus it gives rise to the common gag:

A: Gimmie a [short time period]
B: Okay ::Rummages in pockets/coin purse::

FTR MeMum calls all small-order coins en mass "shrapnel" and I agree with her there.

I am going to have to ponder 'bit' and where it fits in the economy. Possibly a five Second coin or other such piddly loose change.