Will I be able to wear 8 rings as an octopode after dragon form and necromutation?

What happens to octopodes when they transmutate? Will their rings meld into their body?

The wiki article on dragon form says this:

All equipment except for rings and amulets meld into your body

So does that mean I will be able to keep my 8 rings on?

What about necromutation?

The other posted answers were probably correct in 2012, but in modern versions of crawl, octopodes get 8 rings in all forms. You can be a dragon with 8 rings now.

As you would expect, you lose the extra rings when you transmute into a form that does not have 8 arms. That means the first two rings you have will remain equipped, but the other six will be unequipped.

According to the source code, Octopodes keep all eight rings only when they transmute into a spider (quelle surprise!).

The source code shows that any form that keeps mutations will allow all eight rings as well. Spider is a special case as it does not keep mutations but allows 8 rings.

The non mutation forms are lich, blade hands, statue form and beastly appendage as seen in the below code snippet constants. A separate piece of code takes each piece of equipment off depending on whether its a ring at ring locations 3-8 and whether it meets keep-mutation or spider form in which case it declines to remove the ring.

Reference:

bool form_keeps_mutations(transformation_type form)
{
    switch (form)
    {
    case TRAN_NONE:
    case TRAN_BLADE_HANDS:
    case TRAN_STATUE:
    case TRAN_LICH:
    case TRAN_APPENDAGE:
        return true;
...
}

Goes to removal code snippet:

    // Octopodes lose their extra ring slots (3--8) in forms that do not
    // have eight limbs.  Handled specially here because we do have to
    // distinguish between slots the same type.
    if (i >= EQ_RING_THREE && i <= EQ_RING_EIGHT
        **&& !(form_keeps_mutations(form) || form == TRAN_SPIDER))**
    {
        result.insert(eq);
    }