Can familiars grow with extra HD?

[Cold_Iron]

So my magus has a gravity elemental familiar using improved familiar. As his hit die are considered equal to mine douse he get bigger with more HD?

[LazarX]

Familiars don't have Hit dice, so they don't gain feats or skills. They have effectively shadow hit dice for the purposes of how spells react on them but they have half their master's hit points as well as having his skill ranks.

[Samasboy1]

Yeah, the familiar doesn't gain any actual HD, so it doesn't get bigger.

[Cold_Iron]

So no giant black holes as familiars understandable but worth a shot.

[partyrico]

Gravity elementals are a much higher power level than the other familiars anyway. At will telekinesis or reverse gravity and immunity to small ranged weapons (arrows?) is much more powerful than the other familiars' abilities.