Can you polymorph into Cornugon, or other outsiders?

[neochaos]

Well, while I was reading a polymorph spell description as following:

This spell functions like alter self, except that you change the willing subject into another form of living creature. The new form may be of the same type as the subject or any of the following types: aberration, animal, dragon, fey, giant, humanoid, magical beast, monstrous humanoid, ooze, plant, or vermin. The assumed form can’t have more Hit Dice than your caster level (or the subject’s HD, whichever is lower), to a maximum of 15 HD at 15th level. You can’t cause a subject to assume a form smaller than Fine, nor can you cause a subject to assume an incorporeal or gaseous form. The subject’s creature type and subtype (if any) change to match the new form.

I found that the description doen't says that you can polymorph into an outsider. But, I saw a lot of articles listing outsiders as "polymorph-able" monsters....I'm confused. Please give me decent explanation.

[Iku Rex]

"This spell functions like alter self, except that you change the willing subject into another form of living creature. The new form may be of the same type as the subject or any of the following types: ... "

You can polymorph into an outsider if you have the outsider type. Example: aasimar.

[Akimbo]

Example two, Otherworldly Feat.

Example three, Star Elf Sorcerer specializing in Polymorph and Planar Binding.