That is not what it does.
In addition to these benefits, you gain any of the natural attacks of the base creature, including proficiency in those attacks. These attacks are based on your base attack bonus, modified by your Strength or Dexterity as appropriate, and use your Strength modifier for determining damage bonuses.
If a polymorph spell causes you to change size, apply the size modifiers appropriately (see Table: Ability Adjustments from Size Changes), changing your armor class, attack bonus, Combat Maneuver Bonus, and Stealth skill modifiers. Your ability scores are not modified by this change unless noted by the spell.
Unless otherwise noted, polymorph spells cannot be used to change into specific individuals. Although many of the fine details can be controlled, your appearance is always that of a generic member of that creature's type. Polymorph spells cannot be used to assume the form of a creature with a template or an advanced version of a creature.
When you cast a polymorph spell that changes you into a creature of the animal, dragon, elemental, magical beast, plant, or vermin type, all of your gear melds into your body. Items that provide constant bonuses and do not need to be activated continue to function while melded in this way (with the exception of armor and shield bonuses, which cease to function). Items that require activation cannot be used while you maintain that form. While in such a form, you cannot cast any spells that require material components (unless you have the Eschew Materials or Natural Spell feat), and can only cast spells with somatic or verbal components if the form you choose has the capability to make such movements or speak, such as a dragon. Other polymorph spells might be subject to this restriction as well, if they change you into a form that is unlike your original form (subject to GM discretion). If your new form does not cause your equipment to meld into your form, the equipment resizes to match your new size.
While under the effects of a polymorph spell, you lose all extraordinary and supernatural abilities that depend on your original form (such as keen senses, scent, and darkvision), as well as any natural attacks and movement types possessed by your original form. You also lose any class features that depend upon form, but those that allow you to add features (such as sorcerers that can grow claws) still function. While most of these should be obvious, the GM is the final arbiter of what abilities depend on form and are lost when a new form is assumed. Your new form might restore a number of these abilities if they are possessed by the new form.
You can only be affected by one polymorph spell at a time. If a new polymorph spell is cast on you (or you activate a polymorph effect, such as wild shape), you can decide whether or not to allow it to affect you, taking the place of the old spell. In addition, other spells that change your size have no effect on you while you are under the effects of a polymorph spell.
If a polymorph spell is cast on a creature that is smaller than Small or larger than Medium, first adjust its ability scores to one of these two sizes using the following table before applying the bonuses granted by the polymorph spell.
Okay, so.
What you get:
+10 Disguise check to looking like the thing you turn into.
Bonuses listed in Form of the Dragon I or II (including base speed).
Your gear melds into your body but you keep the bonuses from static items (belts of physical stat, headbands of mental stat, cloaks of resistance, amulet of natural armour or mighty fist etc).
You lose any Ex or Su ability based on race NOT class, all of your Dragon Disciple stuff will keep working.
You will lose class features dependent on the presence of your racial abilities, you do not have any of those.
Dragon Disciple Natural Armour Increase is an increase to natural armour so will apply to armour you get from Form of the Dragon.
Dragons are specifically mentioned as able to cast spells, if you have Eschew Materials you can cast any spell without an expensive material component on your spells known.
You're also proficient with any of the new forms natural weapons, so dragon claw/bite/tail/wing.
EDIT: You're also functionally immune to polymorph effects while already affected by one. Or, you can have the new one apply instead of the old one.
NP :>
Edit: Just to be clear, when I say 'static items' that does not include armour or shields.
Thanks from me as well, Aioran. My Dragon Disciple has been away for a while, and she's making a comeback tomorrow leveled up with the Dragon Form ability. I was kind of overwhelmed by the wall of text that is the polymorph section (combined with the actual spell). Your bullet points are quite helpful.
Nice to know that I can still use my spells and bloodline abilities while in dragon form, but it's still kind of underwhelming when you think about it. I get a boost to Str and Con and several extra natural weapon attacks, but weaker versions of everything else I can already do without turning into a dragon. And the dragon is still only medium sized. That's not very intimidating at 12th level. =(