Bass clef

This is the symbol for notes below middle C - in piano music, a bass clef is often used for the left hand.

The spaces are:

A.C.E.G.   All Cows Eat Grass

And there are a few ways to remember the lines:

G.B.D.F.A. Gorillas Buy Donuts From Asda
           Great Big Dogs Fight Animals
           Green Buses Drive Fast Always
           etc

But I like the first one!

Treble clef is above middle C.