accessing ports on mega

How do I access the full 8 bit port instead of bit by bit on the mega ?.
I could do it before on the Diecimila broad with PORTC and DDRC etc , but with the Mega I must be missing something.
With the sheet I`ve got on mega pins it says pins 22 to 29 are PORT A and pins 30 to 37 are PORT C
0 bit means input and 1 an output in the DDR , So DDRA 0x00 and DDRC 0x00 should make port a & c inputs.
Now setting PORTA and PORTC to 0x00 should pull the port low.

If I move PORTA & C to a variable eg

DDRA = 0x00
DDRC = 0x00
PORTA = 0x00
PORTC = 0x00

Void loop()
{
Whatever_a = PORTA
Whatever_c =PORTC
Serial.print ( whatever_a , DEC ) and the same for port c
}

If I connect any of the pins 22 to 37 high , all I`m getting is 0 , 0 from both ports
What have I missed ?

I`ve worked it out !!!
I should be using PINA and PINC
eg
Whatever_a = PINA
Whatever_c = PINC
Serial.print ( whatever_a , DEC )