Hi guys, I an almost done my Pokedex for the Hoenn region, but I need to..

Gorebyss&Huntail:Trade Clamperl with a Deepseascale/deepseatooth to evolve.
Cascoon: Evolve Wurmple.
Masquierain: Evolve Surskit, but you'll need to trade Surskit from another game.
Shedinja: When you evolve Nincada, keep an extra space in your Pok'eball slot, and after evolution, Shedinja will appear.
Snorunt:Deep inside the Ice Path north of MossdeepCity.
Latias: Trade from Sapphire or use an AR to go to Southern Island.

Gorebyss/huntail:get a scanner from the abandoned ship,trade it with capt stern and you will be asked to get a deepseatooth or a deepseascale.Once you choose one give it to clampearl and trade.
Cascoon:in petelburg woods,or evolve a wurple and hope it's a cascoon.
Masquarian:Evolves from a surskit which you only can get in Ruby.
Shedninja:have a pokeball in your bag,and when your nincada evolves into a ninjask it will be in your party.Make sure there is ONE space in your party no more and no less.
Snorunt:In shoal cave near Mossdeep.
Latias:On southern island which you need a eon ticket to get there.you can only get a eon ticket with a cheat device.

Gorebyss comes from trading Clamperl with Deepseascale attached, and Huntail comes from trading it with Deepseatooth; Cascoon is in Petalburg Woods; Masquerain evolves from Surskit at level 22; Snorunt is in the icy chamber of Shoal Cave; Shedinja appears in an empty party slot when Nincada evolves into Ninjask; Latias is found along the eastern side of Hoenn if you selected 'Red' when your mother questioned you about the broadcast when you returned from the League.

-Gorebyss: Trade over Clamperl holding deepseascale.
-Huntail: Trade over Clamperl holding deepseatooth.
-Cascoon: Petalburg Woods.
-Masquerain: Evolve a Surskit.
-Shedinja: Have a space open in your party, and a ball in your pocket you caught you Nincada in, then evolve your Nincade at level 20. You'll get a Ninjask and Shedinja.
-Snorunt: Shoal cave, in the ice area.
-Latias: Southern island.

Check there location for them on your pokedex or trade from anoter game.

Hope I help

Hey Blazer
Gorebyss and Huntail are the evolved forms of Clampearl, To get Gorebyss you have to give your Clampearl the item Deepseascale and then trade it with a friend. You do the same to get Huntail except that you give it Deepseatooth instead. You can choose to get on of these items from Captain Stern after you have given him the scanner I think.

Cascoon is the evolved form of Wurmple. The thing is that a Wurmple can either evolve into a Silcoon or a Cascoon, so you can never be sure when you evolve it which it will turn into, but if you can't be bothered doing that, you can catch Cascoon in Petalburg Woods.

Masquerain is the evolved form of Surskit, and I think it evolves at level 32 or 36.

Now to get Shedinja you need to evolve a Nincada, but you have to have a spare space in your party and a spare pokeball. When you evolve Nincada into Ninjask, Shedinja will also appear in your party.

You can find Snorunt in Sholl Cave (the one near Mosdeep). But it can only be found in the icy depths of the cave so you'll have to wait for the tide to go out. As far as I know the tide goes out at 6:00pm or around there, I'm pretty sure, depending on what time you have set in the game.

Finally, finding Latias/ Latios can be alot of work. After you've beaten the Pokemon leage and you have chosen either red/ blue, you can find it. Look for it in the grass. Just keep looking and you'll eventually find it,one hint though is try not to fly anywhere because that will cause it's location to reset. If you want, you can also buy heaps of Max Repels so that the only Pokemon you will find will be Latias, but this option can be costly.

Well, I hope I helped and happy hunting!

Gorebyss and Huntail are from trading a Clampearl, but you need to make it hold one of the two items, Deepseatooth or Deepseascale.