Beast Shape I (lvl 4):

When you cast this spell, you can assume the form of any Small or Medium creature of the animal type. If the form you assume has any of the following abilities, you gain the listed ability: climb 30 feet, fly 30 feet (average maneuverability), swim 30 feet, darkvision 60 feet, lowlight vision, and scent.
Small animal: If the form you take is that of a Small animal, you gain a +2 enhancement bonus to your Dexterity and a +1 natural armor bonus.
Medium animal: If the form you take is that of a Medium animal, you gain a +2 bonus to your Strength and a +2 natural armor bonus.

Beast Shape II (lvl 6):

This spell functions as beast shape I, except that it also allows you to assume the form of a Tiny or Large creature of the animal type. If the form you assume has any of the following abilities, you gain the listed ability: climb 60 feet, fly 60 feet (good maneuverability), swim 60 feet, darkvision 60 feet, low-light vision, scent, improved grab, pounce, and trip.
Tiny animal: If the form you take is that of a Tiny animal, you gain a +4 enhancement bonus to your Dexterity, a –2 penalty to your Strength, and a +1 natural armor bonus.
Large animal: If the form you take is that of a Large animal, you gain a +4 enhancement bonus to your Strength, a –2 penalty to your Dexterity, and a +4 natural armor bonus.

Beast Shape III (lvl 8):

This spell functions as beast shape II, except that it also allows you to assume the form of a Diminutive or Huge creature of the animal type. This spell also allows you to take on the form of a Small or Medium creature of the magical beast type. If the form you assume has any of the following abilities, you gain the listed ability: burrow 30 feet, climb 90 feet, fly 90 feet (good maneuverability), swim 90 feet, blindsense 30 feet, darkvision 60 feet, low-light vision, scent, constrict, ferocity, improved grab, jet, poison, pounce, rake, trample, trip, and web.
Diminutive animal: If the form you take is that of a Diminutive animal, you gain a +6 enhancement bonus to your Dexterity, a –4 penalty to your Strength, and a +1 natural armor bonus.
Huge animal: If the form you take is that of a Huge animal, you gain a +6 enhancement bonus to your Strength, a –4 penalty to your Dexterity, and a +6 natural armor bonus.
Small magical beast: If the form you take is that of a Small magical beast, you gain a +4 enhancement bonus to your Dexterity and a +2 natural armor bonus.
Medium magical beast: If the form you take is that of a Medium magical beast, you gain a +4 enhancement bonus to your Strength and a +4 natural armor bonus.

Elemental Body I (lvl 6):

When you cast this spell, you can assume the form of a Small air, earth, fire or water elemental. The abilities you gain depend upon the type of elemental you change into. Elemental abilities based on size, such as burn, vortex, and whirlwind, use the size of the elemental you transform into to determine their effect.
Air elemental: If the form you take is that of a Small air elemental, you gain a +2 enhancement bonus to your Dexterity and a +2 natural armor bonus. You also gain fly 60 feet (perfect), darkvision 60 feet, and the ability to create a whirlwind.
Earth elemental: If the form you take is that of a Small earth elemental, you gain a +2 enhancement bonus to your Strength and a +4 natural armor bonus. You also gain darkvision 60 feet, the push ability, and the ability to earthglide.
Fire elemental: If the form you take is that of a Small fire elemental, you gain a +2 enhancement bonus to your Dexterity and a +2 natural armor bonus. Your base land speed also increases by 10 feet. You gain darkvision 60 feet, resist fire 20, vulnerability to cold, and the burn ability.
Water elemental: If the form you take is that of a Small water elemental, you gain a +2 enhancement bonus to your Constitution and a +4 natural armor bonus. You also gain swim 60 feet, darkvision 60 feet, and the ability to create a vortex.

Elemental Body II (lvl 8):

This spell functions as elemental body I, except that it also allows you to assume the form of a Medium air, earth, fire, or water elemental. The abilities you gain depend upon the type of elemental you change into.
Air elemental: As elemental body I except that you gain a +4 enhancement bonus to your Dexterity and a +3 natural armor bonus.
Earth elemental: As elemental body I except that you gain a +4 enhancement bonus to your Strength and a +5 natural armor bonus.
Fire elemental: As elemental body I except that you gain a +4 enhancement bonus to your Dexterity and a +3 natural armor bonus.
Water elemental: As elemental body I except that you gain a +4 enhancement bonus to your Constitution and a +5 natural armor bonus.

Elemental Body III (lvl 10):

This spell functions as elemental body I, except that it also allows you to assume the form of a Large air, earth, fire, or water elemental. The abilities you gain depend upon the type of elemental you change into. You are also immune to critical hits and sneak attacks while in elemental form.
Air elemental: As elemental body I except that you gain a +2 enhancement bonus to your Strength, +4 enhancement bonus to your Dexterity, and a +4 natural armor bonus.
Earth elemental: As elemental body I except that you gain a +6 enhancement bonus to your Strength, a –2 penalty on your Dexterity, a +2 enhancement bonus to your Constitution, and a +6 natural armor bonus.
Fire elemental: As elemental body I except that you gain a +4 enhancement bonus to your Dexterity, a +2 enhancement bonus to your Constitution, and a +4 natural armor bonus.
Water elemental: As elemental body I except that you gain a +2 enhancement bonus to your Strength, a –2 penalty on your Dexterity, a +6 enhancement bonus to your Constitution, and a +6 natural armor bonus.

Elemental Body IV (lvl 12):

This spell functions as elemental body I, except that it also allows you to assume the form of a Huge air, earth, fire, or water elemental. The abilities you gain depend upon the type of elemental you change into. You are also immune to critical hits and sneak attacks while in elemental form and gain DR 5/—.
Air elemental: As elemental body I except that you gain a +4 enhancement bonus to your Strength, +6 enhancement bonus to your Dexterity, and a +4 natural armor bonus. You also gain fly 120 feet (perfect).
Earth elemental: As elemental body I except that you gain a +8 enhancement bonus to your Strength, a –2 penalty on your Dexterity, a +4 enhancement bonus to your Constitution, and a +6 natural armor bonus.
Fire elemental: As elemental body I except that you gain a +6 enhancement bonus to your Dexterity, a +4 enhancement bonus to your Constitution, and a +4 natural armor bonus. Your base land speed also increases by 20 feet.
Water elemental: As elemental body I except that you gain a +4 enhancement bonus to your Strength, a –2 penalty on your Dexterity, a +8 enhancement bonus to your Constitution, and a +6 natural armor bonus. You also gain swim 120 feet.

Natural attacks:

Primary natural attack: BAB + Str modifier to hit, +Str modifier to damage.
Secondary natural attack: BAB + Str modifier - 5 to hit, + 1/2 Str modifier to damage.