Ferrothorn
well usually Pokemon that are in your pokedex are Pokemon that you have seen in the wild or in battle with another trainer/gym leader/ childhood friend. There are 493 Pokemon up to date. Once the 6th generation (5th Gen. is Sinnoh.) of Pokemon comes out (Pokemon Black and White) there will be more Pokemon.
Glaceon http://www.serebii.net/pokedex-dp/471.shtml
If you look at psypokes you will notice that it is rotom
By seeing all 150 Pokemon and then showing your pokedex to Prof. Rowan in Sandgem town at his lab. Their should be a cut scene where Prof. Oak comes and gives you the national pokedex.you see all the Pokemon in the pokedex then go to sandgem town and speak to professor rowan he'll give you the national pokedex.
Once you have seen every Pokemon in the Sinnoh region go to sandgem and talk to the professer-he gives it to you and professer oak comes along and updates your pokedex into a national pokedex
Unown is the Pokemon that comes after Snorlax in the Sinnoh Pokedex.
terrakion
In the pokedex, spoink.
Stunfisk.
well usually Pokemon that are in your pokedex are Pokemon that you have seen in the wild or in battle with another trainer/gym leader/ childhood friend. There are 493 Pokemon up to date. Once the 6th generation (5th Gen. is Sinnoh.) of Pokemon comes out (Pokemon Black and White) there will be more Pokemon.
Misdreavus
its evolved form, masquerain
Rotom does.
Glaceon http://www.serebii.net/pokedex-dp/471.shtml
Its Phione in Pokemon Platinum, You can get it by breeding a Manaphy and a Ditto Actually; Rotom comes after Manaphy in the Platinum pokedex. Kthnx. http://pokemon.marriland.com/platinum/pokedex/list/sinnoh/ Rotom comes after manaphy in the platinum pokedex phione can be made by breeding a manaphy and a ditto but he's actuelly not in the platinum pokedex :D
After Latios comes Kyogre, the legendary Pokemon for Sapphire Version.
In the National Pokedex, where Weavile is number 461, Magnezone is after Weavile. In the Sinnoh Pokedex, where Weavile is number 145, Uxie is after.