Try, try again (Breeding)

[Lady Leaf]

Player name(s): Leaf
Character names(s): Lance Rossi
Pokemon species and genders: Shiny Haxorus (F) and Shiny Sceptile (M)
How many eggs you would like: 3
Which character(s) the egg(s) will go to: Lance Rossi
Cost of the breeding: 600

Player name(s): Leaf
Character names(s): Sen Onni
Pokemon species and genders: Shiny Ponyta (M) and Shiny Deerling (F)
How many eggs you would like: 3
Which character(s) the egg(s) will go to: Sen Onni
Cost of the breeding: 600

Player name(s): Leaf
Character names(s): Kero Blackthorn
Pokemon species and genders: Sigilyph (M) and Leucistic Swanna (F)
How many eggs you would like: 3
Which character(s) the egg(s) will go to: Kero Blackthorn
Cost of the breeding: 600

Grand Total: 1800

[Jay]

Species: S.Axew - S. Treecko x 3
Date Received: 7/12/2011
Date to Hatch: 7/26/2011

Species: S.Ponyta - S. Deerling x 3
Date Received: 7/12/2011
Date to Hatch: 7/26/2011

And Sigilyph and Swanna are incomparable.

[Lady Leaf]

veekun.com/dex/pokemon/swanna

On here it says they are compatable... so why are they incomparable?

[Jay]

Bulba says they weren't but *shrugs* Serebii says they are. >_> M....

Sigilyph - Leucistic Ducklett
Date Received: 7/12/2011
Date to Hatch: 7/26/2011