Parts of balls initially bitten by large snakes (8)

'parts of balls' is the definition.
'bladders' can be an answer for 'parts' (bladder is a kind of part). I'm not sure about the 'of balls' bit.

'initially bitten by large snakes' is the wordplay.
'initially' suggests taking the first letters.
'by' means one lot of letters go next to another.
'large' becomes 'l'.
'snakes' becomes 'adders' (adder is a kind of snake).
The initial letter of 'bitten' is 'b'.
'b'+'l'+'adders'='BLADDERS'

Can you help me to learn more?